| 摘要 |
An FSK receiver deciding the pass band width of a pass band limiter according to a frequency departure is provided to implement high-sensitivity reception according to the various designs of the frequency departure and frequency stability of transmitter by determining the modulation sensitivity according to the pass band width. An FSK receiver(100) comprises a 1-stage low-noise amplifier(1), a mixer(2), an IF(Intermediate Frequency) band-pass filter(3), an IF limiter amplifier(4), an FSK detector(5), a comparator(6), a PLL(7) and a control block(8). The 1-stage low-noise amplifier amplifies the FSK high frequency signal which is received from the frequency departure. The mixer receives the output signal of the said furnace right - noise amplifier and output signal of PLL. The mixer outputs the intermediate frequency signal. PLL produces the local signal. The control block controls the pass band width of the IF BPF and modulation sensitivity of the FSK detector. The control block comprises the outside control terminal.
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