Mitsubishi Denki Kabushiki Kaisha

Eiji Arita

Hiroyuki Nakayama

Masahiko Nakamura

Yoshiki Mizutani

Toshiya Adachi

Akiko Takahama

Yoichi Asamoto

Shigehiro Tamaki

Tomohiro Ushio

An image reproduction apparatus which converts a sampling frequency from a first frequency to a second frequency, performs interfield interpolation at a third frequency, and converts the sampling frequency from the third frequency to the first frequency, wherein the interfield-interpolation is performed at the first frequency between signals one field apart from each other. The apparatus also converts a number of vertical scanning lines to convert a high definition TV signal of the MUSE format to a signal of NTSC format, sets a scanning period used in the vertical scanning line conversion, and generates a coefficient used in the vertical scanning line conversion.

Image reproduction apparatus performing interfield or interframe

A MUSE-NTSC converter of a relatively simple and small scale circuit design. An oscillation signal from a 28.63636 MHz oscillator (20) is eight times as large as a subcarrier frequency fsc. A Y image processing circuit (17) and a chroma encoder (18) can perform various kinds of processing, such as dividing a frequency of the oscillation signal from the 28.63636 MHz oscillator (20) and the like, to produce a subcarrier frequency. A signal separating circuit (3') receives the oscillation signal from the 28.63636 MHz oscillator (20) as a single system clock and performs some kinds of signal processing which vary from a full wide mode to a zoom mode. Thus, in performing PLL on system clocks in the MUSE mode and the NTSC mode, there may be only one PLL circuit (21) for synchronizing an oscillation signal from a 32.4 MHz oscillator (19) and the oscillation signal from the 28.63636 MHz oscillator (20) in phase.

Muse-NTSC converter having two oscillators

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Nagaokakyo, Japan

Eiji Arita