| 摘要 |
<p>This receiver has a circuit (30) for judging whether or not a specific DC voltage range is drawn into an FM demodulation circuit (14). If the circuit (30) judges the range to be not drawn, this circuit (30) turns off a switch (27) and cuts the negative feedback loop, and controls an LPF circuit (25) constituting a PLL circuit (26) for selecting an audio channel to switch over a switch (29) to apply the output voltage (Vτ) of the LPF circuit (25) to a VCO (20). If the circuit (30) judges the range to be drawn, the circuit (30) turns on the switch (27) to establish the negative feedback loop, and then, controls an LPF circuit (28) having a time constant greater than that of the LPF circuit (25) to switch over the switch (29) to apply the output voltage (Vτ) of the LPF circuit (28) to the VCO (20).</p> |
