NTSC high resolution television converting apparatus for converting television signals of an NTSC system into high resolution television signals

• US 5,134,479 A
• Filed: 02/11/1991
• Issued: 07/28/1992
• Est. Priority Date: 02/16/1990
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ohishi, Tomofumi
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US07/653,824
• Time in Patent Office: 533 Days
• Field of Search: 358/140, 358/141, 358/11, 358/12
• US Class Current: 348/556
• CPC Class Codes: H04N 7/0122 the input and the output signals having different aspect ratios

Abstract

A video signal based on an NTSC system is converted into a signal for EDTV. The converted signal is subjected to signal compression in a signal compression ratio of 910/m times. The compressed signal is added with a pedestal level signal and a side level signal. The combined signal is converted into an analog signal, and thereafter primary color signals R, G and B are generated to be imaged on a high resolution television monitor. Thus, the original video of the NTSC system can accurately be reproduced with respect to a high resolution television monitor with an aspect ratio of 16:9.

Claims

1. An NTSC high resolution television converting apparatus for converting a video signal based on an NTSC system into a video signal of a high resolution television system in order to display said video signal based on the NTSC system onto a high resolution monitor television receiver having a different aspect ratio, said apparatus comprising:

signal processing means for converting said video signal based on said NTSC system into a video signal for an EDTV;

time-base compression processing means for signalcompressing a video display period of an output signal of said signal processing means in a signal compression ratio of 910/m times in a horizontal direction, where said m is an integer in which the signal compression ratio n is within ±

2% with respect to a signal compression ratio n₀ when m=1237 is set as a reference value; and

signal switching means for switching between an output signal of said time-base compression processing means and a side level signal to be entered in a blank space produced when a time-base is compressed, to supply the switched signal as an output.

2. The NTSC high resolution television converting apparatus according to claim 1, wherein

the compression ratio of said video display period is n, and a denominator and a numerator constituting the compression ratio n both include an integer of two digits.

3. The NTSC high resolution television converting apparatus according to claim 1, further comprising:

write clock signal generating means for generating a write clock signal synchronized with said video signal of said NTSC system; and

read clock signal generating means for generating a read clock signal by multiplying by m/910 the write clock signal generated by said write clock signal generating means, wherein

said time-base compression processing means comprises a line memory for serially writing the output signal of said signal processing means in response to the write clock signal generated by said write clock signal generating means and reading said written signal in response to the read clock signal generated by said read clock signal generating means.

4. The NTSC high resolution television converting apparatus according to claim 1, further comprising:

pedestal level extracting means for extracting a pedestal level from the output signal of said signal processing means to supply a pedestal level signal as an output; and

side level signal applying means for supplying said side level signal as an output, wherein

said signal switching means comprises means for selecting the side level signal supplied as an output from said side level signal applying means in predetermined timing, then selecting an output signal of said time-base compression processing means and thereafter selecting said side level signal, and then selecting the pedestal level signal supplied as an output from said pedestal level signal applying means.