| 摘要 |
The circuit includes a band selector which in one state controls the passage of a first band of frequencies (e.g. UHF signals) via a counter to a first input port of an Amplifier-Multiplexer (AMP/MUX) and which in another state controls the passage and amplification of a second band of frequencies (e.g. VHF signals) applied to a second input port of the AMP/MUX. When the band selector is in the one state, the stages of the counter are activated and only signals in the first band are coupled through the counter and through the AMP/MUX to additional count down stages connected to the output(s) of the AMP/MUX. In the other state, the stages of the counter are inactivated to prevent oscillations and feed through, and only signals in the second band are coupled through the AMP/MUX to the additional countdown stages. |
