AM / SSB receiver production, AM / SSB Receiver
Keywords: AM receiver production, homemade AM / SSB receiver
This receiver is used to receive radio stations, amateur stations, and radio signals of radio stations, amateur stations, and service radio waves, medium wave and short-wave bands. The idea of making a receiver has been previously, but the mature circuit structure or article cannot be found in the Internet and the radio magazine. Since there is no satisfactory circuit form, then let me design, develop it! First, determine the following conditions: - Simple - Vasive - Cheap - Etroence as much as possible trying to have the experiment you can do, and finally determine the circuit introduced in this article, steal the circuit from these experiments - this circuit The design is very successful to fully meet the above requirements. The receiver is simple and feasible, nor does it use non-standard filters and quartz oscillations. Technical indicators of receivers: operating frequency 0.1 - 30 MHz SSB sensitivity. 1881.5 mKV AM sensitivity. 1881. 2 MKV IF (frequency conversion) frequency пч: 1 - 61.925 MHz2 - 10.7 MHz3 - 455 kHz (Note: Russian letter пч - IMF or inverter, by readers themselves itself) Frequency selectivity: Depending on the 455 kHz filter (the selective large selectivity) mirror channel selectivity: 1 - intermediate frequency > 80db 2 - intermediate frequency > 70db3中频 > 70dB (large extent on the quality of the filter 10.7 MHz) Synthesizer tuning step length: - 100 Hz - 1 kHz - 10 kHz - 100 kHz2 convertible VFO10 unit does not adjust memory work mode and frequency Display accuracy to 1 kHz ам mode precise display frequency, SSB is determined by 455 kHz homoscope, which is not considered in the program. Powered voltage +12 V Dimensions: 150 x 150 x 50 MM function schematic simple clear: Receiver circuit schematic: The received signal passes through the external (disconnected) attenuator into the fixed input filter, long wave, medium wave section strong station weakness The signal is successfully completed by the C3L2 second stage high frequency filter, and the seventh-stage low frequency filter (cutoff frequency 30 MHz) achieves selectivity in the first intermediate frequency mirror channel. Next, the received signal enters the mixer DA1 (Model: ADE-1E-SMD, similar to the Western normal model: SBL-1). This ordinary diode mixer (very good for production) can be produced by 4 diodes and 2 ferrite coil transformers in accordance with the specification circuit. The local oscillator signal + 7dBm from the synthesizer enters the second input of the mixer. Results of frequency conversion In the mixer output, a 61.925 MHz first intermediate frequency signal is formed, along the line enters the matching gain limiter located on the left triode Q1, and then enters the first intermediate frequency band filter to suppress 10.7 MHz (40.525 MHz). The second mid-frequency mirror channel. The filtered signal passes from the second feet of the triode Q6 into the second mixer, and the second pin enters the vibration signal 51.225 MHz (multiplier X5) returns from the triode Q4. The 10.7 MHz second ratio of the L9C28 loop enters the second mid-frequency filter, inhibits the mirror channel of the third mid-frequency 455 kHz (10.245 - 0.455 = 9.79 MHz). After filtering, the second intermediate frequency signal enters the forwarder Q8, and then enters the integrated circuit DA2 TDA1083 input (completely equipped with к174ха10), enlarged and enters the integrated circuit internal mixer, and the local oscillator signal 10.245 MHz (Q2) is then passed. 455 kHz third intermediate frequency signal From the fourth output of the integrated circuit into the TDA1083 intermediate frequency line, and completes enlargement and visual frequency here. In addition, the signal is output from the intermediate frequency output into the mixing detector (the second foot of the tertiary tube Q13), from the second foot (SSB mode) into the local oscillator signal 455 kHz (Q11). The audio signal enters the ам / SSB (VD1VD2) mode from the field effect transistor, and the зч signal is attenuated in the TDA1083. The с42 is enlarged and output by a speaker or headset. Three-pole Q3, Q5, Q7 is an electronic rectifier. The SSB open signal enters the receiver SSB connector from the control board. To convert (in the necessary case) single-sided tape reception at Q9, an electronic switch is set, when the USB / LSB connector лог.1, the с55 capacitance on the casing is turned on, in the intermediate frequency filter ачх (automatic frequency synchronization) The 455kHz homoscope moves on the low slope. The three-stage tube Q10, Q12 forms an S-Mobil amplifier. Synthesizer circuit Schematic: Frequency Synthesizer Follow the single cycle PLL synthesizer (minimum tuning step length 100 Hz) circuit diagram, the local oscillator uses DDS frequency synthesizer AD9835 (what is the cheapest one). The signal amplifier is assembled at the tertiary tube Q1, re-adjusting the wavelength between 62.025-91.925 MHz by means of the volatile diode. In set the buffer amplifier in Q3, the amplifier signal enters the transmit repeater Q4, Q5 from its output. From Q4 output into the receiver mixer, from the Q5 to the frequency distributor 100 (can be used in other existing digital integrated circuits, as long as 2 conditions: 1. Pulse number frequency. 1882.100 MHz; 2. Total decomposition coefficient is equal to 100) DD1, DD2, DD3. Then 620250-919250 Hz frequency signal enters the frequency-phase detector DD4, DA3, from the output terminal offset signal into the signal amplifier varactor diode, фапч closed loop. The DDS Synthesis Position Signal Frequency 620250-919250 Hz, the second input of the frequency-phase detector in the low frequency filter L3L4C11C14C19 and Q2 amplifier. The signal amplifier changes 1 Hz per tuning 100 Hz DDS frequency.
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