Hitachi, Ltd.

Yoshihiro Arakawa

Takeo Yamada

Masanori Ogino

Miyuki Ikeda

Akio Nakashima

Toshiyuki Kimoto

Tsuneo Fujikura

Shunji Iwabuchi

Kenji Ando

An adaptive crosshatch signal generator includes a frequency detector for detecting a horizontal scanning frequency, a square calculator supplied with the detected output of the frequency detector, and a variable pulse width multivibrator controlled to have an output pulse width substantially in inverse proportion to the squared output. Longitudinal lines of a crosshatch signal are formed by the output pulses of the multivibrator. The crosshatch signal has a longitudinal line width which is always substantially equivalent to the distance between adjacent scanning lines and is generated by using a simplified configuration irrespective of input signal format.

Adaptive crosshatch signal generator

A convergence correction circuit according to the present invention has a phased locked loop including a programmable counter. The programmable counter has programmable count start and end points. The output of the programmable counter is supplied to a memory storing convergence distortion correcting data therein. As the horizontal screen size is increased, a value closer to the lower limit 0 of the start point as compared with that taken when the horizontal size is small is set as the count start point of the programmable counter, and a value closer to the upper limit (2.sup.7 -1) of the end point as compared with that taken when the horizontal size is small is set as the count end point. In accordance with the horizontal screen size, the count start and end points of the programmable counter are changed. Correct convergence correction is performed even if the horizontal screen size is changed.

Convergence correction circuit

A vertical deflection output circuitry for a television receiver wherein two transistors are connected in single ended and push-pull relation, and the output junction point of the two transistors is connected, to a D.C. power source for supplying a higher voltage than that of a power source for the vertical deflection output circuitry, through a switch which is turned off during the vertical scan period and turned on during the vertical retrace period.

Vertical deflection output circuitry for television receiver

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Yokohama, Japan

Yoshihiro Arakawa