| 摘要 |
A demodulator and frequency conversion circuit handles FM signals. The frequency is reduced in stages, with at least one intermediate frequency signal being produced. The input signal (1) passes to a phase modulator (2); where it is mixed with a signal from a tuning switch (9). An oscillator (4) produces a signal which is mixed (3) with the output of the phase modulator. The mixer stage output connected to a filter stage (5), which is followed by a demodulator (7). The demodulator output (10) is connected to the tuning switch (9). It is also connected to a tuning switch (8) with connections to individual filter elements (6).
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