| 摘要 |
<p>Self-programming scanning receiver having superheterodyne circuitry (12, 14), microprocessor (24) controlled synthesized frequency tuning circuitry (22), frequency validation means (26, 27), a learn mode to invoke the frequency validation means for all frequencies tunable by the tuning circuitry, listen mode for scanning of frequencies learned in the learn mode, and an ignore mode for erasing frequencies from permanent memory. The frequency validation means comprises a detector (14) output connected to a high pass filter (26) input, high pass filter output connected to a noise detector (27), noise detector output connected to a first A/D converter input, algorithms stored in microprocessor program memory for analyzing A/D samples obtained via first A/D for squelch condition, detector output also supplying the input of a low pass filter (54), output of low pass filter connected to a second A/D converter input, algorithms for analysis of A/D samples obtained from second A/D to determine sufficiency of modulation level and lack of digital waveforms, electrically alterable permanent memory (33) for storing information identifying voice channels.</p> |
