| 摘要 |
A noise blanker is disclosed which blanks out impulse noise emanating from the alternator, ignition systems of motor vehicles, and other sources. This is accomplished by delaying an input IF signal while generating a blanking gate pulse occurring at the same time as the noise pulses. These blanking pulses are then used to turn off the delayed IF signal precisely where the noise occurs, resulting in noise-free audio reception. The noise blanker operates to detect noise pulses by detecting the leading edge of any narrow pulse which is received at the front end of the receiver and is reflected in the IF input signal. At the same time, by virtue of the operation of an AGC amplifier the noise blanker's vulnerability to interference or capture by continuous-wave signals is reduced.
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