| 摘要 |
PURPOSE:To facilitate an easy preset and to prevent the tuning shift after end of the preset to perform the display of the channel number by sweeping the local oscillation frequency at the channel selection time and stopping the sweepage when the coincidence is obtained between the count value of the counter and the memory contents. CONSTITUTION:Electronic tuner 1 contains the voltage control type local oscillator, sweeps the oscillation frequency of the oscillator via tuning voltage sweeper 6, and transmits the output of the oscillator to filter 2 composed of elastic surface wave element SAW. Here, the local oscillation frequency is swept in sequence at each reception band at the preset time, and the data of counter 5 along with the band information are written into memory 7 via tuning signal detector circuit 9. And the memory contents is read out at the channel selection time for channel display 15, and also the local oscillation frequency is swept to stop the sweepage when the coincidence is obtained between the count value of counter 5 and the memory contents. Thus, the preset is facilitated with no tuning shift after preset, and the channel number can be displayed automatically. |
