发明授权
US4392249A Electronic channel selection apparatus with surface acoustic wave device 失效
具声表面波装置的电子通道选择装置

Electronic channel selection apparatus with surface acoustic wave device
摘要:
There is disclosed an electronic selection apparatus comprising a surface acoustic wave comb filter, in which the local oscillator frequency of an electronic tuner is swept up to a frequency higher than a peak frequency of the surface acoustic comb filter corresponding to a desired channel number (an upward direction), and then swept toward the opposite direction (a downward direction) until a predetermined number of peaks of the comb filter is counted while checking the presence of an AFC signal, whereby an erroneous tuning operation may be prevented, provided that the signal of the desired channel is present within a predetermined range in the vicinity of the receiving frequency of the desired channel.
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