Sanyo Electric Co., Ltd.

Yosuke Mizutani

Yoshihiro Hori

Akihiko Yamashita

Seiya Ota

Yoshikazu Asano

Shuji Yanase

Kazuo Naganawa

Takehiko Asano

Syuji Yanase

Shinichiro Kitagawa

A video signal converter comprising a frequency setting circuit, a first clock generator, a second clock generator, an analog-to-digital converter, a line conversion ratio setting circuit, a number of scanning lines converter, a frame memory, a writing controller, a reading controller and a digital-to-analog converter is disclosed. The frequency setting circuit sets a first frequency Fi which satisfies a formula: Fi.ltoreq.(To.times.Fo)/Ti, where Ti is a horizontal scanning period of a first analog video signal, To is a horizontal scanning period of a second analog video signal and Fo is a second frequency. The line conversion ratio setting circuit sets a line conversion ratio R which satisfies an equation: R=m/k, based on a width-to-height ratio 1/m of each pixel of the first digital video data and a width-to-height ratio 1/k of each pixel of second digital video data. The number of scanning lines converter converts any digital video data having a first number of scanning lines to varied digital video data having a second number of scanning lines, the second number of scanning lines being R-times the first number of scanning lines. The writing controller memorizes the first digital video data into the memory in synchronization with the first clock of the first frequency Fi. The reading controller reads the first digital video data from the memory in synchronization with the second clock of the second frequency Fo to generate the second digital video data.

Video signal converter

A MUSE sound decoder detects a broadcasting/non-broadcasting identification flag included in the control signals in an applied MUSE signal to determine whether the MUSE signal is broadcasted or non-broadcasted. The MUSE sound decoder further includes a frame synchronization protection circuit for protecting frame synchronization over a predetermined frame synchronization protection time period when the frame synchronization pattern is not detected at the proper timing. The frame synchronization protection circuit sets the frame synchronization protection time period to a long time period when the MUSE signal is determined to be a broadcasted MUSE signal, and to a short time period when the MUSE signal is determined to be a non-broadcasted MUSE signal. Appropriate muting of a sound signal can be carried out according to the condition of the received MUSE signal.

Broadcast/non-broadcast MUSE signal sound decoder with a variable

An apparatus (MD) for reproducing, by a low-frequency replacement method, a noise-free high definition video (MUSE) signal obtained by band-compressing the high definition video signal in a time-compressed integration Sub-Nyquist encoding system so as to include no aliasing noise in a low-frequency component below 4 MHz. This reproducing apparatus includes a converter (3) for converting a reproduced or received MUSE signal into digital data and a memory (7) for outputting feedback data in which preceding by two fields and data preceding by four fields with respect to the current field are alternately arranged, a circuit (6; 33) for replacing/non-replacing the data preceding by four fields by first data corresponding to the current field data from the current field data and the feedback data and deriving a data train in which the first data and the data preceding by two fields are alternately arranged. Output from the data train deriving circuit is employed to be converted to composite data by a mixture 11, and a circuit (LC) for replacing the low-frequency component of the current field data or the first data with the low-frequency component of the composite data. The reproducing apparatus further includes a circuit (15, 18, 19, 19, 54; 15, 35; 34, 15', 54') for inhibiting this low-frequency replacement as well as replacement of the data preceding by four fields and the first data upon generation of noise such as dropout in the reproduced MUSE signal.

Apparatus for demodulating sub-nyquist sampled video signal and

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Gifu, Japan

Yosuke Mizutani