Title:
COMPARATOR OF HIGH FREQUENCY AMPLITUDE MODULATION SIGNALS
Document Type and Number:
Japanese Patent JPH03117085
Kind Code:
A
Abstract:
PURPOSE: To realize a high-sensitivity comparison circuit for harmonic amplitude modulation signal using a high-pass filter, a variable gain amplifier, a multiplier, a low-pass filter, a capacitance amplifier, etc., to constitute an input circuit of a comparison device. CONSTITUTION: In the comparison circuit for signal of a video tape recorder which can be operated with a first head in the 'standard time' mode and can be operated with a second head in the 'long time' mode and can be operated in the 'search mode', outputs of equal legs 41 and 42 connected to two head are connected to the inputs of the same comparator 56 to be selected in the 'seartch mode'. Legs 41 and 42 are in series, and each of them consists of a capacitance amplifier 49 consisting of a high-pass filter 45, a variable gain amplifier 46, a multiplier 47 which multiplies a signal itself, a low-pass filter 48, and a second comparator 50 which supplies a current to the output. Thus, the high-sensitivity comparison circuit for harmonic amplitude modulation signal is realized.
Inventors:
FUIRITSUPU PEROO
JIYANNRU JIYAFUARU
JIYANNRU JIYAFUARU
Application Number:
JP21512590A
Publication Date:
May 17, 1991
Filing Date:
August 16, 1990
Export Citation:
Assignee:
SGS THOMSON MICROELECTRONICS
International Classes:
G01R19/165; G11B5/027; H04N5/783; H04N5/93; H04N5/931; (IPC1-7): G01R19/165; G11B5/027; H04N5/93
Attorney, Agent or Firm:
Keiichi Yamamoto