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公开(公告)号：US3864636A
公开(公告)日：1975-02-04
申请号：US34310073
申请日：1973-03-20
发明人： FUKUDA TAKEO , TORII KENICHI , NISHIBAYASHI KAZUO
CPC分类号： H03J7/24 , H03J5/0272 , H03J7/28 , H03L7/20
摘要： A harmonics generator for simultaneously producing a plurality of frequency spectra with the frequency separation equal to that of a plurality of channels, and a sweeping oscillator which initiates to sweep upon receipt of start-of-sweep signal to vary its oscillation frequency and which stops to sweep upon end-ofsweep signal to hold the frequency at the time the sweep was terminated are provided. A band pass filter is provided for deriving a beat signal when a predetermined frequency difference has appeared between the harmonics generator frequency and the sweeping oscillator frequency. Means are provided for deriving marker signals corresponding to respective channel positions from the output of the band pass filter. By counting the marker signals or by determining the coincidence of a marker signal with the tuning signal from a TV receiver set, a desired channel or channel through which electric wave is being transmitted may be selected and at the same time the frequency of the sweeping oscillator may be held constant by means of an automatic frequency control (AFC) circuit.
摘要翻译： 一种谐波发生器，用于同时产生具有等于多个通道的频率间隔的多个频谱的扫频振荡器，以及扫描振荡器，其在接收到扫描起始信号时开始扫描以改变其振荡频率并停止至 扫描结束扫描信号以在扫描结束时保持频率。 提供带通滤波器，用于当谐波发生器频率和扫频振荡器频率之间出现预定的频率差时导出差拍信号。 提供了用于从带通滤波器的输出导出与各个信道位置对应的标记信号的装置。 通过对标记信号进行计数或通过确定标记信号与来自TV接收机组的调谐信号的一致性，可以选择正在发送电波的期望信道或信道，并且同时扫描振荡器的频率 可以通过自动频率控制（AFC）电路保持不变。
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公开(公告)号：US3736513A
公开(公告)日：1973-05-29
申请号：US3736513D
申请日：1971-06-28
发明人： WILSON D
摘要： A harmonic generator produces simulated station signals which are heterodyned in the mixer stage of a receiver. A local oscillator of the receiver is swept through its frequency bandwidth, producing an IF pulse each time the receiver tunes one of the simulated stations. The IF pulses are counted, and upon reaching a number preset on station selection switches, convert the sweep circuit to an AFC amplifier, maintaining the receiver tuned to a desired station frequency.
摘要翻译： 谐波发生器产生在接收机的混频器级中被外差的模拟站信号。 接收机的本地振荡器扫过其频率带宽，每当接收机调谐一个仿真站时产生IF脉冲。 IF脉冲被计数，并且在站选择开关上达到预设的数字后，将扫描电路转换为AFC放大器，将接收机调谐到所需的站频率。
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公开(公告)号：US3614666A
公开(公告)日：1971-10-19
申请号：US3614666D
申请日：1970-05-28
CPC分类号： H03J7/28
摘要： In a system for automatically tuning a ringing circuit, the voltage vs frequency curve of the ringing circuit is incrementally scanned and compared to a reference voltage. The frequency increments are made twice as large in that portion of the curve above said reference via a second incremental means. When the curve passes its maximum and returns to the reference voltage, the second means is disabled, reducing the frequency interval by one-half thus setting a frequency which corresponds to the maximum of said curve.
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