| 摘要 |
Tone detection circuitry including tone decoder providing a free running frequency determined by timing resistance and timing capacitance connected to it. A control means including a programmable microprocessor establishes a retrieval record based on the product of the timing resistance and timing capacitance needed to establish the center frequency of the tone decoder for a plurality of bandwidths. The retrieval record is used to establish the product of the timing resistance and timing capacitance when a tone within the selected bandwidth is to be detected. |
