Victor Company of Japan, Limited

Matsushita Electric Industrial Co., Ltd.

Mitsuru Hayakawa

Yasuaki Watanabe

Yukio Okabe

Daisuke Murakami

Yuichi Ikemura

Yasuhiro Fujita

A variable phase shifting circuit comprising a phase splitter for distributing an input signal supplied thereto into first and second output signals which are outputted therefrom and 90 degrees out of phase each other, a first double balanced differential amplifier to which the first output signal from said phase splitter is delivered as a first input signal, a second double balanced differential amplifier to which the second output signal from said phase splitter is delivered as a second input signal, a summer for summing the respective first and second output signals from said first and second double balanced differential amplifiers to output the summed result, a converter for converting a control input supplied thereto to a differential current, first logarithmic conversion means for converting said differential current of said converter to a first logarithmic voltage, circular function conversion means for converting said differential current of said converter to a circular function current, and second logarithmic conversion means for converting said circular function current of said circular function conversion means to a second logarithmic voltage, thus to control the gain of said first double balanced differential amplifier respective to said first logarithmic voltage, and to control the gain of said second double balanced differential amplifier responsive to said second logarithmic voltage, thereby to provide a phase controlled output signal from said summer.

Variable phase shifting circuit

A limiter circuit has an input versus output characteristic which is non-linear in a region outside a linear operating range thereof, so that an input voltage thereof converges to a predetermined voltage within the linear operating range even when the input voltage is outside the linear operating range of the limiter circuit.

Limiter circuit

In a subcarrier regeneration circuit for color television receivers, a phase detector output is sampled by a signal sample-and-hold circuit and a bias sample-and-hold circuit to develop a voltage between the outputs of the two sample-and-hold circuits to control the frequency of a 3.58 MHz subcarrier generated by a voltage controlled oscillator. The oscillator output is phase shifted by 90.degree. and applied to one input of the phase detector for comparison with a gated color burst. The signal sample-and-hold circuit samples the phase detector output during the interval of the color burst, while the bias sample-and-hold circuit samples the phase detector output during an interval which is substantially equal to the flyback interval minus the color burst interval.

Subcarrier regeneration circuit for color television receivers

A variable frequency oscillator comprises an oscillating loop and a variable phase shifter for imparting one of two different phase shifts depending upon the polarities of a DC control voltage to a signal from the oscillating loop. The phase-shifted signal has its amplitude controlled by the amplitude of the control voltage and is combined with the signal in the oscillating loop. The vector sum of the combined signals determines the phase angle of the oscillator signal and hence the frequency thereof.

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Yokohama, Japan

Mitsuru Hayakawa