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Carrier frequency As early as the end of the 2000s, my country had begun to use the single-sideband transmission system in international wireless circuits. Shanghai Zhenru International Radio was built in 1931, which is a single sideband radio station. Single sideband technology entered the field of professional radio communications, which gradually developed after World War II. Regarding the technical and economic value of single sideband system, it has been published in various radio newspapers and periodicals, and this article will not go into details. This article only introduces the basic principles, manufacturing and debugging of the phase-shifting single-side-band transmitter, one of the single-sideband standards, for reference by professional enthusiasts.
The focus of single sideband transmitter is “single sideband electronic signal generator”. As we all know, sideband electronic signals are amplitude modulated products. After the fundamental frequency F is amplitude-modulated by audio, it becomes an amplitude-modulated wave F ± f, which includes the fundamental frequency F and two (upper and lower) sidebands +f and -f. (Note: The early telephone system stipulated that the audio bandwidth was 300~2700Hz. With the improvement of transmission fidelity requirements, the wireless circuit has been expanded to 300~3400Hz. For professional radio communication machines, focus on improving parts efficiency, often compress the audio bandwidth to 300~2000Hz, or even to 300~1500Hz). From the mathematical expression of the amplitude-modulated electronic signal, it can be shown that the phase of the modulated sideband component changes with the phase change position of the carrier frequency. For example, a double-sideband electronic signal:
If the phase of the carrier frequency and audio frequency is shifted by 90° before amplitude modulation, the double-sideband electronic signal obtained by the trigonometric function law will be
(1) Compared with (2), it can be seen that the signs are opposite. Therefore, if the voltages of the two sideband electronic signals of eDSB and e’DSB are added or subtracted, the lower sideband or upper sideband electrons can be obtained. signal. The task diagram of this method is shown in Figure 1. In the figure, OSC is a radio frequency oscillator. Its input voltage is divided into two channels, one is sent to the balanced amplitude modulator BM1; the other is sent to the balanced amplitude modulator BM2 through the 90° phase-shifting network N. B is the audio amplifier, one of its input voltages is directly sent to BM1, and the other is sent to BM2 through the 90° phase-shifting network P. In this way, a double sideband voltage eDSB with a controlled carrier frequency can be obtained at the input end of BM1. Similarly, BM2 also inputs a double sideband electronic signal voltage e’DSB with a carrier frequency suppressed. If these two voltages are added or subtracted through the addition and subtraction amplifier ± A, a required lower sideband or upper sideband electronic signal can be obtained.
The difference between the block diagram in Figure 2 and Figure 1 is that BM1 and BM2 not only implement balanced amplitude modulation, but also implement the addition or subtraction of the phase shift signal, and do not set separate addition and subtraction amplifiers. Its specific working procedure is: the amplified audio electronic signal is divided into two parts through the phase-shifting network P. The voltage amplitudes of the two parts are equal and the phase difference is 90°. The radio frequency oscillation electronic signal input is also divided into two parts with equal amplitude and 90° phase difference.
This 90° phase-shifted audio and radio frequency resolution enters the curtain grid and control grid of the two balanced amplitude modulators. The two sets of balanced amplitude modulators electronically share the same tank circuit. When the two sets of amplitude modulators are balanced with each other, the slots There is no carrier frequency current on the path, and the carrier frequency is restrained. As long as one of the high and low sidebands of the audio output is canceled and the other sideband is superimposed, there will be an electronic signal input. The input electronic signal is the superimposed single-sideband electronic signal. If the input power of the balanced amplitude modulator is high enough, , can be sent directly to the antenna for transmission.
It is actually very simple to obtain single-sideband electronic signals by the phase-shifting method, but it is actually very difficult to phase-shift all the sounds by 90° several times with all the pairs. At present, the more ideal way of audio shifting is to use the “Dum” network, as shown in Figure 3. The network consists of two sets of capacitors and resistors, and the component values are marked in the figure.
The outstanding advantage of the phase-shifting method is that it does not require a complicated circuit structure. Sideband separation occurs at higher frequencies, which greatly reducesThe series of reduction and frequency conversion. The main oscillation frequency can be directly used as the transmitting frequency without the need for a frequency converter. However, compared with the filtering method, the phase-shifting method has poor sideband suppression performance, and is affected by the stability of the components, and the target stability is not ideal enough. To meet the basic target requirements of professional communications equipment, accurate and stable phase-shifting network components must be selected, and the amplifier must work in a minimum distortion state to fully avoid the generation of high-order harmonics.
There has been a long debate about which phase-shifting method and filtering method are better. If adjusted properly, both methods can achieve good results. The special adjustment of the phase-shifting method SSB machine can also achieve 30dB sideband suppression and carrier frequency control, which can meet the requirements of professional single-channel communication machines.
An example of manufacturing a phase-shifting single sideband transmitter (Block Diagram 2). The circuit design is shown in Figure 4. The input of this unit can be sent directly to an antenna for QRP applications or Jamaica Sugar as an actuator for a power reducer. When V1 ~ V4 applies 6SK7 screen voltage 100V, the input power reaches 3W, and applies 6V6 screen voltage 380V~400V, curtain grid voltage 100V, the input power is 40W PEP. Figure 4: Manufacturing example of phase-shifting single sideband transmitter circuit design.
Circuit working principle
IC1 amplifies the audio to the required level (8Ω 1.6V 300mW), and transforms the impedance into 10KΩ C.T. (center tap) through matching transformer T1, which is phase-shifted with the audio Networks R1~R6 and C1~C provide sufficient audio voltage. The 90° phase-shifted audio voltage is sent to IC2 and IC3 for two-way power amplification. The push-pull secondary of T2 performs amplitude modulation on the curtain JM Escorts pole of the first balanced amplitude modulator BM1 (V1, V2), and at the same time, T3 Modulate the amplitude of the two curtain grids of the second balanced amplitude modulator BM2 (V3, V4). While IC2 and IC3 modulate the amplitude of BM1 and BM2, SW2 changes the input phase of T2, so that its input is offset or superimposed in two sets of parallel push-pull balanced amplitude modulators to select the required sideband electronic signals.
Two sets of balanced amplitude modulators made of V1~V1, each set of two control gates are connected in parallel and are stimulated by the same radio frequency. Only the phase difference between BM1 and BM2 is 90°. The two curtain grids of each group are also push-pull connected and are subject to the same audio amplitude modulation. The phase of the amplitude modulation stimulation of the two groups is Jamaicans EscortAlso 90° different. BM1. The two screen poles in each group of BM2 are also push-pull connected, and the two push-pull screen circuits of BM1 and BM2 are connected in parallel, using matching input channels.
The RF oscillator supplies two sets of parallel RF phase shift circuits (RP1LP, RP2CP) from the RF voltage input by T5. The gate resolution of the two sets of balanced amplitude modulators obtains radio frequency stimulation from these two sets of phase shift circuits. The first phase shift circuit consists of a 300Ω resistor RP1 and a 300Ω inductor LP connected in series. The second phase shift circuit is a 300Ω resistor RP2 and a 300Ω capacitor CP in series. The total impedance of two sets of phase shift circuits connected in parallel is 300Ω. Each set of balanced amplitude modulator outputs receives radio frequency stimulation through a 1000P coupling capacitor. The bias voltage is obtained by the gate resistor, or a fixed bias voltage can be set (-1.5V when using 6SK7, -4.5V when using 6V6). The input tank of this machine can work at 7, 14, and 21MHz, and is switched by SW4. The first gear is 7MHz, and the second gear is 14 and 21MHz.
The main oscillator stage of the radio frequency oscillator consists of Q1, L0, C0, C’, C” and forms a capacitive three-point VFO. Due to the use of a field effect tube oscillator, it has a zero temperature coefficient, so the frequency is very stable. The L0 inductance is is 1.6uH, between C0MAX and C0MIN, the oscillation frequency covers the range of 6.96MHz~7.18MHz. Q2Q3 forms a feedback isolation amplifier to eliminate the impact of load changes on the oscillation frequency. The Q3 emitter input load P3 potentiometer is used to control 6SK7 or Different RF stimulation power required by 6V6. Q4 uses 600MHz field effect tube VNF-310 to form a 1.5 ~ 30MHz network broadband amplifier with T4 and T5. Its maximum output power can reach 20W. This unit is used in low power conditions. Input 3W.
All RF oscillators (Q1, Q2, Q3, Q4) are installed in a 100 To facilitate heat dissipation, the C0 and P3 handles extend out of the shell for easy adjustment. The input tank LTCT resonates at 6~25MHz, covering three professional frequency bands (SW4 is at the 1st level), 14MHz and 21MHz. It is tuned on the second and third multipliers respectively (SW4 is in the 2nd position), and the frequency change is very convenient. However, when working in the multiplier state, the input power response drops (21MHz input at 6SK7 is only 0.6W)
This machine is SSB. It is used for both SSB and CW. When speaking, SW1 is turned to the SSB side. When speaking, press the hand button K. The MIC power supply is turned on and the relay Ry is turned on. The power supply Ry is closed and its contacts are turned on.2 and 3 turn the antenna electronic receiving to transmitting, and the contacts 5 and 6 will short-circuit the receiving antenna terminal to ground. At this time, P1 can adjust the voice level.
The CW of this machine uses single sideband to report SSB and CW. SW1-1 connects the low-level T1 to the CW oscillator input, SW1-2, and turns on the Q6 emitter circuit. When the transmitting key KEY sends a code, on the one hand, it switches the Ry antenna from R to T, and at the same time, it turns on Jamaicans Escort A 1KHz CW amplitude modulation oscillator composed of Q5Q6 HTD (0.O2uF), which emits an amplitude modulation electronic signal through T1 and uses HTD to react to the oscillation. Doubles as a CW sidetone monitor. Changing the values on Q5 bias, HTD capacity and Q6 collector resistance can change the oscillation frequency and input level.
The parts are installed on a 300 The tank road coil LT, capacitor C, and input coupling coil L2 are installed on the left side of the base plate. L2 is made adjustable, V1~V4 Author Jamaicans EscortThe experiment uses 6SK7 and 6V6. Readers can also replace other types of four- and five-pole tubes, so the tube base can be considered according to the selected tube type. Figure 5 is configured according to 6SK7 and 6V6, and is installed in the center of the base plate. The RF oscillator is installed on the right side close to the panel, and the C0P3 rotating handle extends out of the box and extends out of the headgear name plate for easy adjustment. Audio reduction IC1, IC2, IC3 and audio phase shifter are installed under the right base plate. See Figure 6 for the panel arrangement. Above are the antenna binding posts AT, AR, ammeter shift switch MK, ammeter, coupling ring L2 adjustment, the center is the CT dial, the upper right corner is the CW side sound hole, and the bottom is the C0 dial and P3. From left to right, the bottom plate is SW4, CT knob, SW3, SW2, SW1, P3, P1, MIC hole, and KEY hole. On the back is the power jack and ground wire terminal.
The power supply part of this machine is an independent power supply box. The power supply schematic diagram is shown in Figure 7. To prevent high-frequency coupling from the power feeder, the high-voltage line from the power supply to the transmitter feeder should be a shielded line and one end should be grounded.
When this machine is used as a QRP, it uses 6SK7, the screen voltage and curtain voltage are all 100V, the output power is 4.8W, and the maximum undistorted output exceeds 3W. The maximum output power of the curtain grid is 400mW. Two sets of balanced amplitude modulators are provided by two LM386s, IC2 and IC3, to provide curtain grid amplitude modulation.When the working voltage is 6V, the maximum output power can reach 600mW. The secondary voltage of T2 and T3 is as high as 76V, which will cause excessive amplitude modulation. Therefore, whether a 10uF capacitor is added between IC2 and IC3 pins 1-8 should be connected or not. Depends on detailed AM depth. When the author uses 4X6V6, adding this capacitor is better than not connecting it; 4X6SK7 is otherwise. In short, the criterion is not to lose the truth. According to the 6SK7 EP-IP characteristic curve, the maximum stimulus voltage in the linear range of its operating curve should not exceed 16V (GI-GH), which requires that the maximum output power of Q4 should not be >0.9W (adjusted by P3). And the two audio abbreviations of IC2 and IC3JM Escortssmall appliancesJamaicans SugardaddyThe source cannot share the same power supply with IC1 to avoid affecting the phase relationship between IC2 and IC3. Therefore, this circuit uses a multi-stage filtering and voltage stabilization method to isolate it.
The fundamental frequency of the radio frequency phase-shifting network in the two bands of 7, 14, and 21MHz is the same 6.96~7.18MHz. The middle frequency of the 7MHz segment is 7.05MHz; the middle frequency of 14MHz is 14.175MHz, and the middle frequency of the base frequency should be 7.0875MHz; for 21MHz, it is 7.075MHz. The middle fundamental frequency difference of the three segments is 7.0875-7.05MHz = 0.0375MHz, lacking 38KHz. Therefore, LP can be calculated as (7.05+7075+7.0875) / 3 = 21.2125 / 3 = 7.0708MHz design to get 6.7526uH (take 6.8uH). Similarly, LP=75P. The test results are the same as setting LP and CP in three sections, so the reader can remove SW3 and only change LP to a modulating type and CP to a variable capacitor. There is no need to move it after one calibration. QSY is also used. No impact. The RF phase shift circuit is directly welded to the RF output end of the balanced amplitude modulator, and the wiring should be as short and thick as possible.
RF edge oscillator frequency calibration: Connect the power supply and gradually turn on the high-voltage power supply. Press K. The transmitter is in the transmitting state, P1 drops to zero, and the receiver (common for communication) ) is close to Q1, C0 is located at the maximum capacitance, find the oscillation frequency of Q1 from the receiver dial (several points may appear), open the receiver distance, and send it to the strongest point of the electronic signal. The frequency of this point should be 6.8 MHz around. C0 is located at the minimum capacitance. According to the above method, this point should be around 7.2MHz.Otherwise, the L0 distance should be fine-tuned to obtain the frequencies of these two points. After rough adjustment, check point by point to mark the frequency of each point. When calibrating the frequency of each point correctly, the receiver should be placed in the receiving position, the beat frequency should be in the middle position, and the middle point of the correction frequency should be at the zero beat point. After calibration, three bars can be calibrated. The outermost is the 7MHz segment, followed by 14MHz and 21MHz. You only need to set the 7MHz scale correctly, and the other two bars only need to mark the corresponding points with 2 times and 3 times the value. The quantitative representation is shown in Figure 8.
Adjust Q4 working point: P3 is located at the address, adjust P4 so that the gate voltage of Q4 is 2V, and the source current is 300mA. At this time, the static output power is 7.2W, and the Class A reduced output power is about 3W. Calibration of the balanced amplitude modulator input tank circuit: Connect the high-voltage power supply and do not connect the antenna and dummy load. Set the transmitter SW1 to the CW bit, and use the detector in Figure 9 to sparsely couple the coupling ring in Figure 9 to the LT. Set C0 to 7.050MHz, press KEY to quickly adjust CT, send it to the detector ammeter and record the maximum point (SW4 is set to “1”), and release KEY. The second step is to set C0 to 14.175MHz, set SW4 to “2”, press the KEY, adjust CT, select the maximum command as above, and quickly release the KEY. The third step is to place C0 at 21.2XMHz and select the maximum point according to the above method. CTLT coarse adjustment completed. The above tuning is performed under the condition that the LTCT has no load. When the load is connected, the LT inductance will decrease, and the dial must be fine-tuned. SW1 is set to the SSB position, and the MIC hole outputs a 400Hz sine wave electronic signal of 1mV. Adjust P1 to measure the terminal voltage T at the low level of T1. The calibration position is shown in Figure 10. Amplitude modulator equalization adjustment: When the audio output drops to zero, adjust P5 and P6 to make the detector indicate zero. If the zero point cannot be found, it means that the μ value or Gm value of the tube is different. Change the position of the tube to make an appropriate match and pursue the output balance. Otherwise, it should be Try another tube. What should be clarified here is that when 6SK7 is changed to 6V6, or 6V6 is changed to 6SK7, the balance should be re-adjusted. Initially, the high-frequency voltage measured at the 50Ω load terminal should be 2mV/50Ω. Sideband suppression detection: For professional manufacturers, it is relatively difficult to detect sideband suppression indicators, and can only be determined qualitatively with the help of finished SSB receiver components. The method is: put the transmitter SW2 on USB; SW1 on SSB. Handshake key K speaks to MIC. The receiver receives and transmits electronic signals at the LSB of the SSB, and can only hear the slight rhythm of speech but cannot clearly distinguish the internal events of the specific speech. The same situation is the same as above when sending LSB and receiving USB. At this time, the sideband suppression separation of the transmitter can basically meet the minimum requirements. If this requirement cannot be met, check R1~R6, CWhether the values of 1~C6 meet the requirements, whether the audio power supply is connected to the radio frequency electronic signal, whether the IC2 and IC3 outputs are balanced, and whether P2 is not adjusted properly. Initial general adjustment: After the calibration procedures of the above parts are completed, the RF stimulation level should be initially calibrated. The method is: still use the detector in Figure 9 (you can also use a high-frequency power meter if you have one) to adjust P3 to reduce the emission stimulus, and at the same time observe the input of the part (press KEY in CW mode). When the sensor is low enough, the stimulus decreases, and the output decreases at the same time. , and the level of encouragement is increased and the input does not decrease. This is the best situation and you can enter the actual task.
Component selection and manufacturing
There are no special requirements for resistors and capacitors. Capacitors marked with M are mica capacitors, those with “+” are electrolytic capacitors, and other capacitors with sufficient withstand voltage can be selected. Both polyester and ceramic capacitors are acceptable. Unless otherwise indicated, the capacitors used in the balanced amplitude modulator shall have a withstand voltage of 500V~450V. Unless otherwise noted, resistors are all 1W. The core resistors of integrated circuits, transistors, and field effect transistors are all 1/4W metal film resistors. Capacitor CT=12/360 double connection, radio type can be used instead.
The audio phase-shifting network is R1~R6, C1~C6 in Figure 4. The detailed numerical calculation is shown in Table 1. The values of the resistor and capacitor components of the phase shift circuit should be quite accurate. The simplest way is to calculate the applicable values of R and C according to the values in Table 1, and use small carbon resistors and mica to obtain them in series and parallel. The first step is to select Jamaica Sugar Daddy based on the “nominal value column” in the table or the one closest to the “requested value column” of capacitor. Then its value is substituted into the formula corresponding to the requested value of R1~R6 to find the applicable value of R.
Table 1: Audio phase shift network design
Example: The measured C1~C6 resolution is Cm1~Cm6, that is, 0.0011, 0.00205, 0.00637, 0.0049, 0.00945, 0.029. Substitute the obtained numerical values into (100/Cm1) ~ (453/cm6) to find the absolute corresponding R1~R6:
R1 = 100 / 0.0011 = 90.90909KΩ (take 90.9, error 2 = 105 / 0.00205 = 51.2195KΩ (take 51KΩ, error 3 = 100 / 0.00637 = 15.6Jamaica Sugar986KΩ (take 15.7KΩ, error 4 = 453 / 0.0049 = 92.449KΩ (take 92.5KΩ, error 5 = 476 / 0.00945 = 50.37KΩ (take 50KΩ, error 6 = 453 / 0.029 = 15.6207KΩ (take 15.5KΩ, Jamaica Sugar Error 1, T2, and T3 have different characteristics, requiring the core inductance coefficient AL to be the same. Usually the AL value given by 2T refers to the minimum AL value of the core. In order to ensure that the transformer parameters are consistent, the one with the same AL can be selected first. In commonly used coils, AL has the following relationship with the number of inductor turns:
AL=L/N2, where L is the inductance (nanohenries nH); N is the number of turns (T)
The AL unit is nH/T2 (Note: This relationship is not suitable for switching circuits). Selection method: first wind a coil (the correct number of turns is known) and install it into the magnetic core, measure its inductance, and substitute the above formula to calculate the AL value. p> This machine uses magnetic core ALJamaicans Sugardaddy=2.34nH/t2, transformer low-level inductance LP = ZP/WfL = 8 / 6.28 x 300 = 4.25mH.
Primary turns ratio η= SQRT (Zp/Zs) = SQRT (8/10×103) = 0.283, N2/N1 = 35:1.
Primary turns Np = SQRT (4.25 x103 / 2.34) = 43T
Number of secondary turns Ns = Np /η= 43×35 = 1050T.C.T. (Dual-wire parallel winding, end-to-end connected)
Primary wire diameter d0 =0.7 SQRT ( SQRT (W/Zp). )) = 0.7 SQRT ( SQRT (0.6/8) ) = 0.37 mm
Secondary wire diameter ds =0.7Jamaicans Sugardaddy SQRT (SQRT (W/Zs)) = 0.7 SQRT (SQRT (0.6/10KΩ)) = 0.062, take 0.12mm
Because IC1, 2, 3 Jamaica Sugar The quiescent current is only 4mA, and the magnet gap does not need to be considered.
L0 = 1.6uH, use Ø 0.65 enameled wire to wrap 15 turns around the 10mm diameter coil tube (one turn can be added to prevent the L value from decreasing due to the shielding box).
LP = 6.8uH, Ø 0.26 enameled wire is tightly wound on a 6mm wooden rod for 38 turns.
LT input channel road ring, use 2mm enameled wire to wind 16 times on a 50mm diameter cylinder, the winding length is 100mm, the two ends and the middle tap are fixed on the porcelain high-leg edge, 5.5 turns inward at both ends The welding end leads out and connects to SW4-(2).
L2 input coupling coil, tightly wound with 2mm enameled wire for 2 turns, connected to the center position of LT (adjustable), diameter 50mm.
T2 uses Ø 0.31mm enameled wire double-wound on the NXO-4O TV double-hole magnet (twisted 3 times/25mm). See Figure 11 for the winding method.
T5 is on the NXO-40 Ø 10 magnetic ring. Three strands of Ø 0.31 enameled wire are twisted and wound 3 times, connected end to end, and connected according to the impedance of 1:9, as shown in Figure 12.
Power supply coordination 6SK7, 6V6 two tube types and transistor, collector circuit requirements, circuit structure and component data are shown in Figure 7. Products that meet the AFC application specifications shown in the picture. The tube circuit, IC, and semiconductor circuit are powered separately to eliminate unnecessary phase interference as much as possible.
The author stopped the test on this experimental road to further understand the functions of QRP and the phase-shifting method. The test results are quite good. A 20-meter oblique antenna was used in Bengbu City, Anhui Province using 6SK7. SWR 1.5 was tested at 14.180MHz with BV2LS and BV4LQ QSO on October 31, 1995. The RST resolution was 54 and 58. On December 25, it was tested with 9V1YX and 7J1ARO. QSO, RST 44 and 43. Harbin Institute of Technology BY2HIT RST 53.7MHz on January 14th. For Shanghai, Guangzhou, Beijing, Hangzhou, and Kunming, the RST is 57~59+.
This circuit is made by the author using the components at hand. The design is not reasonable, and the theoretical description is inevitably omitted and wrong. I hope that professional colleagues will criticize and correct it.
The author is grateful to Mr. Li Xichen of BA1AT and Mr. Xu Yue of BD2RH for providing valuable technical materials, and to Mr. Xu Yujia of BA4CH, Mr. Dong Shicheng of BA7KE, and Mr. Zhou Qizong of BV2LS for their great help and cooperation in experiments and guidance, which are included here. Show genuine gratitude.
References
1. The Radio Amateur’s Handbook, 1977
2. Single sideband electroless communication (written by Wang Qi)
3. The general meaning of radio transmitters (translated by Liao Shijing)
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Attached is 2013-09-21 11:35:27 MCU+TL494+Buck DC/ The DC voltage regulating microcontroller digital-to-analog converts the input reference voltage, and the error amplifier compares the reference voltage and the response to output the PWM waveform. The PWM wave drives the high-end MOSFET TIRF3205 in the Buck circuit after passing through the IR2110. The circuit diagram is as shown in the figure. It is troublesome for everyone to see. Clear, attached 2013-09-21 11:40:20 MCU + TL494 + Buck DC/DC voltage regulator MCU digital-to-analog conversion input reference voltage, through the error amplifier to compare the reference voltage and feedback to complete the output PWM waveform, PWM waveform After IRJamaicans Escort2110 is used to drive the high-end MOSFETIRF3205 in the Buck circuit, the circuit diagram is as shown in the figure. If you are troubled, you can’t see it clearly. 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The teacher leads the mechanical students to learn and accumulate on their own 2020-12-16 10:33:35DSP phase-shifted full-bridge inverter requires a DSP whose PWM can phase-shift similar to the phase-shifting performance of the analog device UC3875, which can be passed through the value of the register or The internal pins of DSP are used to change the phase shift angle. Looking forward to experts’ help and recommendations. The project is urgent! 2018-05-14 03:31:12Keil 5 The execution receiver in debug mode does not receive data. The problem with MCU STM32L476 is this. I execute the program in debug mode and execute the LoRa program in one step. LoRa has execution capabilities and is not available. , the transmitting data receiving end also received it, but after I removed the interrupt, the LoRa program also allowed LoRa to launch, Jamaica Sugar Daddy But the receiving end did not receive the materials. I would like to ask everyone, what is this?Is there any solution… 2018-12-24 09:10:16 Nike Flyknit iidd anex lvjywww. Mosquito put his hands behind his back with a smile on his face, and moved back to the original place handsomely, vaguely carrying the look of a master The style is gone. (:) Ma Chang said angrily on the side: How about it? You see, if it were a fight, the black soldier nike would have died more than a dozen times, so why don’t you thank Mr. Mosquito for showing mercy. Ma 2016-05-20 17:51:18 STM32F407 phase shift misalignment STM32F4 advanced timer TIM1 and TIM8 input two pairs of complementary waveforms. The two pairs of complementary waveforms are misaligned during relative phase shift. How to solve it? 2020-08-04 17:13:41 The results obtained by sending the STM32 serial port to the PC are not consistent. I started to learn STM32. I want to try the STM32 serial port to send to the PC. The source code is as follows. It will send 12 34 to the PC in a loop (the PC also Jamaicans Sugardaddy is 9600) The result of the experiment is that the PC always displays 60 F8. I don’t know why it is like this? Is there something missing in my program? Xie 2014-04 -09 22:51:16What are the French programming ports of STM microcontroller? Has anyone ever used STM8Sxx microcontroller? What are its French burning ports? What is the burning method? What should I pay attention to when burning? A veteran has a question, please give me some advice! {:4_98:}2013-03-15 15:52:16TFDU4300 accept questions? Hello everyone, I would like to ask if you have used the TFDU4300 component. I used the link on page 9 shown below. The infrared emission part was successful. I saw the infrared light emitted with the camera, but the RXD could not receive it. After receiving the information, I don’t know if there are any places where special 2013-11-07 18:12:35 [Original] artificial radio frequency grounding system should be used, and try to keep the shortest distance. Of course, the ground terminal of the transmitter must also be properly connected to the power grounding system. Then connect a wire about 4 meters long to J2. Note that the other end of the wire connected to J2 should be kept open and do not touch any objects, let alone others when working on the machine. It is best to wrap it with tape. 2010-04-19 19:13:53 [Ask for help] Is there any way to capture the changing position of the optical ruler feedback? I just came into contact with Matlab not long ago, and the most recent topic I encountered was “How to capture the changes in the optical ruler feedback” For position, you need to use Matlab (or Simulink) to capture the optical ruler signal, and then convert the signal into a changing position input display. To measure the changing position of the slider (reciprocating position in a single direction), what are the relevant data or methods ( settings) can be used as a reference, please help, thank you 2015-.12-08 15:28:22 What is the difference between llc topology and phase-shifted full-bridge topology? What is the difference between llc topology and phase-shifted full-bridge topology? 2018-12-13 14:40:41pic Microcontroller teaching (seeking senior designer) I want to learn pic microcontroller programming and looking for experts, one-on-one teaching, the required expenses can be negotiated 1660740906 Zhang r2016-09-01 17:20:23qfn moiding Tape Our company has developed a qfn molding packaging tape and is looking for partners nbspJamaica Sugar Daddy; My qq 11574101512010-07-29 03: 32:16How does ucc28950 complete the phase shift of the super forearm and lagging arm? The chip manual only mentions the dead zone programming time of the upper and lower tubes, but it doesn’t say how to phase shift? How does ucc28950 complete the phase shift of the super leading arm and lagging arm? The chip manual only writes about the dead zone programming time of the upper and lower tubes, but does not say how to phase shift. I am a novice, and I humbly ask all the teachers for advice. Please. 2019-03-07 20:37:33 [Atmel WINC1500-XSTK request] The development environment of smart home robot Wifi module can be greatly expanded, which is very suitable for application learning programs of Internet of Things and control robots. :1. Installation of the test program 2. Module test and debug under the test program 3. Program try update and Recompile4.2016-06-30 17:44:07 [LattePanda trial request] Smart home robot project name: Smart Home Robot trial plan: Learning objectives: Good at embedded development, Linux systems and drivers, MCU implementation and design, and have played with many development boards and implemented many small projectsJamaicans Escort, technology is advancing rapidly, which lowers the threshold of development board. It is worth using it to display your creativity. 2017-03-27 10:36:10 [LeMaker Guitar request] Smart home machinery Human, UART, IIC, Serial, etc. 5. Programming for basic home control 6. Change basic control to automated control Jamaica Sugar7 . Provide communication and operation of mobile APP 8. Overall debug 9. Scalable performance learning results: 1. Familiar with the CPU of this development board2016-01-1816:22:50 [MM32F103 trial experience] The situation around unboxing testing and development should be restored to the previous version 6. After the installation is completed, the Package Installer will pop up. The relevant component library has been uploaded by the official, so you can download it here Click the Device tab on the right side of the device and find MindMotion >2016-08-14 10:36:59 [NanoPi2 request] Smart home robot and statistics of valid information Jamaica Sugar can make home robots, access control systems, and central control systems. The S5P4418 new generation CPU will help develop applications. High-speed interfaces and a large number of expansion pins are the advantages of this development board. , the Internet of Things can be used to easily communicate with each device, and use the mobile phone to connect to the Internet 2015-12-02 16:14:23 [Nuvoton ISD9160 voice recognition request] Home security robot designEVB-T335 development board based on Nuvoton ISD9160 development board, I am familiar with the Cortex-A9 development board and stm32 development board. I am familiar with the Cortex M series microcontrollers and can quickly get started with the Nuvoton ISD9160 development board. I hope to borrow one of the Nuvoton ISD9160 development boards 2016-10-24 10:16:03 The golden finger part of the PCB board, coupled with the low setting of the milling cutter position and the ductility of copper, prevent the second stage of cutting from effectively cutting off chips, resulting in copper burr (see the picture below). The golden finger copper burr is on the bevel edge. The manufacturing process is a serious anomaly due to the formation of short circuits. [size2015-02-05 17:39:17 If the collection of traffic voltage is important, here we need to collect the voltage value for the single-phase 110v traffic signal. The method currently thought of is to use a 110v/15v transformer and then divide the voltage through resistors 1/11 times, the signal is raised to above 0v through a clamp circuit composed of a tl074(op). News 2019-06-27 04:35:59 Low-power MCU multi-key touch chip, commonly used in LED lights, Remote controls, etc., LCD TVs, digital photo frames, USB speakers, GPS, multi-function business machines Portable products: MP3, MP4, iPod peripheral products, digital cameras, mobile phone function keys, Bluetooth headsets, Bluetooth speakers, Walkmans, DVDs Players, flashlights, children 2020-04-16 17:46:09 The method of using phase shift circuits to calculate phase. In circuit applications, due to the presence of passive components such as inductors and capacitors, under the action of frequency electronic signals, the capacitors charge and discharge, and the inductors store A process that can release energy, and there will be a phase change in the input and output electronic signals. For capacitive phase shiftingThrough this process, the charging and discharging of the capacitor causes the alternating current in the circuit. Generating current cycle ratio 2022-01-11 09:27:42 Using the Omron NX controller and Sysmac studio to control the simple movement of the motor Using the Omron NX controller and Sysmac studio to control the simple movement of the motor – Surrounding environment configuration 0. Media 1. Actual hardware connection 2. Sysmac studio configuration 2.1 New project 2.2 Communication configuration 2.2.1 In-software communication configuration 2021-09-07 08:06:53 Integrated structure advantages of advanced packaging processes such as WLCSP-TAIKO processes Δ chip thinning When low-temperature processes (metal plating, etc.) are required later, there is no deoxidation phenomenon. Because it is an integrated structure and has a single shape, it can reduce the possibility of particles being brought into contamination. ※ Without the use of hard substrates, etc., the structure (shape) can be maintained by just relying on the chip itself. ) The core area is not burdened during grinding 2019-09-17 09:05:03 The current status and development direction of the global robot industry. The ability to support the development of the human industry also needs to be improved. 4. After explosive development in just three to five years, there may be 700 to 800 domestic robot companies with “certain influence”. However, most of the international industrial robots are concentrated in relatively simple handling, palletizing, home appliances, and metal manufacturing fields. What are the important aspects of high-precision 2015-11-26 17:09:29 baseband testing? What are the important aspects of baseband testing? Baseband testing is not as complicated as RF testing. In addition to power supply and power consumption measurements, what else is there? 2016-05-13 20:54:59 Temperature card based on 51 microcontroller. Some time ago, I made a collection card based on 51 microcontroller to collect 16 channels of temperature data for testing the machine. The AD conversion chip is MAX6675. Since the collection card is Public and company T-type thermocouple high temperature acquisition (Ta~150)JM Escorts. But the accuracy is completely unreachable. 8LSB bit error 2013-11-30 10:18:59 How to use Labview to extract a waveform of a single frequency from a waveform file for analysis? How to use Labview to extract a waveform of a single frequency (such as 200Hz) from a waveform file for analysis in the time domain? I tried using bandpass filtering, but the filtering limit was difficult to set. 2015-10-26 18:21:07How to use Labviewdesign wind turbine wind direction control processHello fellow seniors~ I am new to Labview and I don’t know how to design a wind direction control program for a wind turbine. Can you please give me guidance? Already have tools: NI USB-6008, Wind Vane 2012-10-19 01:17:26 How about Stop arbitrary phase shifting of PWM waves? How to arbitrarily phase shift the PWM wave 2024-03-21 07:46:43 Looking for a development board that meets the needs Looking for a development board I don’t want to add too much development time, so I want to buy a ready-made module. My needs are 1. Yes Networking capabilities (either with or without an operating system) 2. Can accept YUV data from CCD cameras 3. It would be better if it has hardware H.264 compression. Specifically, what you need to do is to be able to conduct online live broadcasts through CCD cameras. Please give me some insights 2017-01-07 18:01:00 Please help me design a phase shift circuit because I have to share the same camera with the FPGA, so there is such a need and trouble! Design a phase shift circuit adjustable from 0 to 180 degrees, high frequency, using amplifier 2017-08-09 18:53:25 Assist in recommending and learning microcontroller emulator models Assisting in recommending and learning microcontroller emulator models; PS: Newcomer! 2011-06-18 00:03:16What is the difference between microstrip line and strip line? What is the difference between microstrip and stripline? And when calculating impedance using ploar software, which one do you choose? 2016-04-30 22:28:54 If you want to learn electrical appliance maintenance and repair, mobile phone maintenance and repair, or software development, what do you need to prepare? If you want to learn electrical appliance maintenance and repair, mobile phone maintenance and repair, or software development, what do you need to prepare? Make a list, such as soldering stations, multimeters, oscilloscopes… and various consumable components and accessories. It is best to recommend specific brand models. Although I am studying, I also want to play. The equipment may not be purchased all at once, but you can slowly put it together and practice while learning. Of course, it would be better if there was a sequence for purchasing equipment. 2015-11-17 21:25:18 Mobile phone baseband material Mobile phone baseband material PPT version 2011-08-16 12:25:34 Anti-oxidation tinned copper braided wire specifications Copper braided tape parameters with different cross-sectional areas `1. Anti-oxidation The specification of oxidized tin-plated copper braided wire is based on the nominal cross-sectional area of 2-1200 square numbers. Taking a copper braided tape of 2 square meters as an example, the strand * set * monofilament wire diameter, reference width * reference thickness, that is, 2 square meters of copper braid Ribbon=24*5*1/0.15=5.0*1.0. 2. Copper 2020-07-16 19:49:41 Introduction to the new generation of robot communication technology “CDBUS” EtherCAT’s forwarding delay and avoidance of complex synchronization problems caused by it). Security: hardware sends and receives data to prevent software bugs from causing bus failures; high timeliness: priority is ensured, and industrial control can even be used Jamaica Sugar Daddy uses its remaining bandwidth to listen to music and watch videos online; supports multiple hosts 2018-04-09 17:27:42 Square wave phase shift circuit, shifting process Is the Chinese square wave a bit unrealistic? ` This post was last edited by Ssvep at 2018-5-8 11:30. The circuit diagram is as follows. There are no problems in the simulation. The starting point and starting waveform of the phase shift are both good. During the phase shift process , there is something wrong with the waveform, why? 2018-05-08 11:28:41 Can a general microcontroller with PWM input SPWM? Can a general microcontroller with PWM input SPWM? 2023-10-28 08:27: 29. Does anyone know how to send attachments? `I had nothing to do, and accidentally found this while looking through old files. I wanted to send it to everyone to understand the situation, and I also asked an expert to give me some advice on how to use the account here. . The file I want to send is too large, and the size is limited here, so I can’t send it in this way. My contact QQ2015-08-24 13:57:55 Has anyone successfully developed stm32? Product? Has anyone successfully developed a product? I am helping the company in the development. It is a stuck machine system. There are many problems to be solved. I hope it can be completed soon!! 2019-08-21 04:35 :01 Has stm32 done full-bridge phase shifting? I have only used DSP to play full-bridge phase shifting. I don’t know whether stm32 can complete the 2018-08-31 16:09:53 sine wave phase shifting circuit simulation problem. Please help me. God explains. Use spice to simulate a sine wave phase-shifting circuit. Why are the positive and negative half-cycle peaks different at the beginning of the input? The white is the waveform after phase shifting, as shown below: 2015-07-14 23:50:17 Find the phase-shifting control of 28335DSP Electronic signal program full-bridge phase shift control requires phase shift control. Has anyone done this? Please give me some guidance on the phase shift control electronic signal program generated by 28335DSP. Thank you. 09:24:45 To add STC’s MCU into the Keil4 phase Jamaica Sugar Daddy dry material download, first open the 51 download tool and click Add Electronic signals and header files are installed in keil under the directory of your keil. Then we can use STC’s microcontroller model at will. Select the microcontroller model or understand the situation as we are familiar with and type in #include “STC12C5A60S2.h” , then open the file and add it successfully!!!!!! Hahaha2022-02-18 06:07:0Jamaicans Sugardaddy2 The development and technical requirements of lead-free solder Introduction to lead-free solder[/td] The development, technical requirements and current status of lead-free solder, etc. [td=2,1] One: Lead-free The growth of lead and its compounds in solder will bring greater harm to the environment and safety around human life. The extensive use of Sn/Pb alloy solder in the electronics industry will cause pollution 2018-08-28 16:02:12Magnet connection. Device pool connectors and other connectors. It also has high-precision mold design, R&D, and manufacturing capabilities, and can undertake customer mold manufacturing orders. The company has now passed the ISO9OO1:2000 quality management system. In order to adapt to the needs of the domestic market, all products. Both are in compliance with the EU WEEE/ROHS green environmental protection 2018-07-07 18:11:02 Encoding and error control encoding and error control error detection code The error detection code can only detect whether there is an error and generate an automatic retransmission request (Automatic When the repeat request (ARQ) protocol detects an error, it discards the data block and requests the transmitter to resend the data block. 2008-10-23 13:37:07 Cellular Wireless Network Cellular Wireless Network Application Multiple Low Power In the 100W low-power transmitter communication area, small cells with independent antennas are divided. Each cell is assigned a frequency band, and adjacent cells including transmitters, receivers and control units will be assigned different frequencies. The antennas of the cells and this change position 2008-10-23 13:55:37 Can the buzzer make a sound? I am new to using Proteus 7.5 on microcontroller. This attachment is Guo Tianxiang’s 51 proteus circuit diagram. It simulates the buzzer but I don’t hear any sound. Does the Proteus software need to be set in 2012? -05-03 16:43:37 How can I copy a question and let others click to open the link? How can I copy a question and let others click to open the link? Sometimes, in order to facilitate others to view a post, I post it. It is better to include a link URL in the title. You can understand the general content of the post by reading the title. However, when I copy the title now, after sending it, it is a simple text copy, not the kind of copy with a link. Please help me. Thank you for your guidance! 2016-04-17 16:13:18 Ask the master what the role of the phase shift network is? 2015-03-12 15:59: 13 How to design a phase shift circuit? 2017-03-18 18:09:22 How to use the ADF4351 to disable the phase shift and set the phase value? Phase shift manipulation? 2019-01-0321:35:40 Is there a phase-shift trigger circuit for DC voltage regulation? Phase-shift trigger circuit for DC voltage regulation 2019-11-07 23:50:38 How does the resistor-capacitor phase-shift bridge trigger circuit achieve phase shift? How does the resistor-capacitor phase-shift bridge trigger circuit achieve phase shift? What does the input pulse width of a monostable circuit depend on? What is resistance measurement method? What are the characteristics of direct coupled reduction circuits? 2021-08-19 07:54:53 High and low temperature tests, should we do low temperature or high temperature first? In the high and low temperature test, which one should be done first, the low temperature or the high temperature? Under low and high temperatures, the transmitter power difference is still quite large, 4-5 dB!!!2016-06-08 21:01:16 Teacher Gao Huantang: For practical education in the AI trend, program design logic is also a means Its important feature is that corporate regulations are given by people and machines will not change them. For example, suppose Sogo Department Store has an anniversary corporate regulation: [If the amount of a single invoice exceeds 1,000 yuan, a 20% discount will be given] Therefore, in traditional informatization Here, the programmer uses program logic as a means to 2020-12-10 11:58:54
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