| 摘要 |
A phase locked loop type of television tuning apparatus includes an apparatus for dividing the frequency of a local oscillator signal by a number equal to the frequency of the local oscillator signal, in MHz, corresponding to the presently selected channel. The divider forms an output signal including first and second portions having durations respectively equal to first and second predetermined numbers of periods of the local oscillator signal. The first number is related to the number of the selected channel. The second number is related to the frequency band in which the selected channel resides. To determine the frequency band of the selected channels, band traversed signals are generated whenever the number of periods of the local oscillator signal generated since beginning of the first portion corresponds to the first channel in a band. When a new band traversed signal is generated, the previous band traversed signal is terminated. The band traversed signal remaining at the end of the first portion determines the band in which the selected channel resides.
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