Title:
HIGH-SENSITIVITY FM DEMODULATING SYSTEM
Document Type and Number:
WIPO Patent Application WO/1983/000973
Kind Code:
A1
Abstract:
A demodulating system for improving in the noise characteristics of a wide band-television (FM) signal. In the system, a band-pass filter (7) is followed by a variable band-pass filter (8) having controllable center frequency and band width for an improvement in the C/N ratio. The band width of the variable band-pass filter (8) is controlled so as to be wide when a received wave is strong and to be narrow when the wave is weak. The center frequency of the variable band-pass filter (8) is controlled in response to the color sub-carrier component (3.58MHz) in a received television signal and, for extracting the color subcarrier component, a narrow band-pass filter is arranged on the output side of a discriminator (9) so as to control the variable band-pass filter (8).
Inventors:
OHTA TOMOZO (JP)
TSUTSUMI YOSHIO (JP)
SUGANO MOTOSHI (JP)
TSUTSUMI YOSHIO (JP)
SUGANO MOTOSHI (JP)
Application Number:
PCT/JP1981/000206
Publication Date:
March 17, 1983
Filing Date:
August 31, 1981
Export Citation:
Assignee:
OKI ELECTRIC IND CO LTD (JP)
International Classes:
H03D3/00; H03G5/24; H04N9/64; H04N11/00; H04N11/24; (IPC1-7): H04N9/50
Foreign References:
| JPS5285455A | 1977-07-15 |
Other References:
NHK Giken Geppo Vol. 20, No. 5 (1977-5) Nippon Hoso Shuppan Kyokai, Konishi Yoshihiro "SHF Jushinki" p. 176 - 181 especially page 179, left column, line 7 from the Bottom to right column, line 19, fig. 2(b).
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