FM Radio IF Sampling Demodulation System
A technology for FM broadcasting and demodulation systems, applied in broadcasting circuit devices, broadcasting receiving circuits, stereo broadcasting receiving, etc., can solve the problems of inability to measure directly, high frequency, etc., and achieve simple structure, high execution efficiency, and high audio signal sampling Effect
Active Publication Date: 2022-02-01
JILIN INST OF RADIO & TELEVISION
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Problems solved by technology
[0003] In order to solve the problem that the frequency of the existing 10.7MHz intermediate frequency signal is too high for the frequency measurement and demodulation system of the single chip microcomputer and cannot be directly measured, the present invention provides an intermediate frequency sampling demodulation system for FM broadcasting
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[0016] combine figure 1 and figure 2 Description of this embodiment, FM radio intermediate frequency sampling demodulation system, including tuner U1, D flip-flop U2, single-chip microcomputer U3, resistor R1, resistor R2, resistor R4, resistor R5, capacitor C1, transistor Q1, transistor Q2, potentiometer R3 and ceramic filter Y1;
[0017] The OUT terminal of the tuner U1 is connected to the capacitor C1, the capacitor C1 is respectively connected to the resistor R1, the resistor R4, and the base of the transistor Q1, and the collector of the transistor Q1 is respectively connected to the resistor R1, the resistor R2, and the base of the transistor Q2 ;
[0018] VCC is connected to the collector of transistor Q2 and resistor R2 respectively, the emitter of transistor Q1 is connected to resistor R5 and the output terminal of ceramic filter Y1 respectively, and the emitter of transistor Q2 is connected to potentiometer R3 and D terminal of D flip-flop U2 respectively Connect...
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FM radio intermediate frequency sampling demodulation system, involving the field of radio and television, to solve the problem that the existing 10.7MHz intermediate frequency signal is too high for the frequency measurement and demodulation system of the single chip microcomputer, and cannot be directly measured, including tuner U1, D trigger U2, Single-chip microcomputer U3, capacitor C1 and oscillating circuit; the present invention adopts the sampling method to realize the demodulation of FM radio monophonic programs, and the present invention only needs to use one DMA to arrange the capture data in the memory, not only without the joint use of multiple DMAs, but also in the interrupt In the service program, the audio sampling value can be calculated once without looping, avoiding the need for multiple collision detections in the interrupt service program in the existing frequency measurement and demodulation system; compared with the existing system, the structure is simple, because the execution efficiency is high, so Higher frequency audio signal sampling is possible.
Description
technical field [0001] The invention relates to the field of radio and television, in particular to an FM radio sampling demodulation system. Background technique [0002] The national standard of FM broadcasting in my country stipulates that FM broadcast programs adopt frequency modulation, and the maximum frequency deviation is 75KHz; the traditional program demodulation method is to use a frequency discriminator to demodulate the intermediate frequency signal to obtain an audio analog signal, and then use an analog-to-digital converter to convert it into an analog signal after amplification. Digitized sound data flow; the existing literature discloses "FM broadcast monitoring and demodulation method for direct frequency measurement by single-chip microcomputer", "FM radio frequency measurement and demodulation electronic system", "Single-chip microcomputer frequency measurement FM stereo demodulation system", and "FM Stereo Frequency Measurement and Decoding System” propose...
Claims
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IPC IPC(8): H04H40/45H04H20/48
CPCH04H40/45H04H20/48
Inventor 焦杰
Owner JILIN INST OF RADIO & TELEVISION