| 摘要 |
A clock-driven pulse source is used to apply repetitive short pulses to the squelch control connection point of the squelch circuitry of a radio receiver to deactivate momentarily the squelch circuitry at regular intervals. This provides periodic noise bursts of "de-squelch" pulses on an otherwise silent radio in order to inform the radio operator that the radio is live and that the volume is adequate. A light may also be connected to the system to provide a second, visual, indicator of the operational status of the radio. This radio receiver operational checking system may also be utilized where there are two or more radios in use by providing an additional clock-driven pulse source for each radio in use. The system may be arranged so that the status of individual radios may be quickly ascertained by sound and/or by light indicators. <IMAGE>
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