Pioneer Electronic Corporation

Hiroyuki Takahori

Akira Nishioka

Yoshihiro Kawanabe

Hideki Fujimoto

Tomihiro Oguchi

Kiyoshi Sugibayashi

A method for tuning a television receiver in which an optimum local oscillator frequency is selected for offset stations. A local oscillator frequency of the receiver is incremented in steps of a first predetermined frequency interval beginning with a frequency at the bottom of an offset band around the center frequency of the local oscillator. As the local oscillator frequency is scanned, when both an up signal, indicative that the tuning frequency is above a predetermined range around the actual frequency of the received signal, and a down signal, indicative that the tuning frequency is below the predetermined range around the center frequency, the local oscillator is decremented by the first frequency interval and then incremented in a second, smaller frequency interval until the up and down signals are both lost. The local oscillator frequency is then increased and decreased by the first predetermined frequency interval, wherein, if both the up and down signals toggle states, the frequency at which both the up and down signals were lost when scanning with the second frequency interval is accepted as the best tuning frequency.

Station selecting method for television receiver

A voltage/current conversion circuit giving an output current which is proportional to an input voltage. The circuit includes an operational amplifier to one input of which the input voltage is applied, first and second transistors, to the commonly connected bases of which the output of the operational amplifier is applied, and a feed-back path connecting the collector of the first transistor to the other input of the operational amplifier. With the circuit thus constructed, the output derived from the collector of the second transistor is in proportion to the input voltage.

Voltage/current conversion circuit

A voltage controlled attenuator includes a control circuit having variable impedance means whose impedance varies in a stepwise fashion as an input voltage is varied. In this manner, the attenuation characteristic of the attenuator can be made to vary stepwise in slope or inclination to improve its efficacy for use as a volume control device in audio apparatus.

Growing community of inventors

Tokyo, Japan

Hiroyuki Takahori