发明名称 |
DIGITAL IMAGE COMMUNICATION EQUIPMENT |
摘要 |
PROBLEM TO BE SOLVED: To improve the S/N of picture signals by controlling the frequency band of analog picture signals to be inputted to an A/D converter. SOLUTION: Analog signals outputted from a video camera 1 are amplified in a preamplifier 2 and then led to an AGC circuit part 3, a peak value or average value of a signal voltage is detected in a signal voltage detection part 31 and a control voltage corresponding to the detected signal voltage is generated in an AGC control voltage generation part 32. The control voltage is fed back to the preamplifier 2 of a preceding stage to control the gain of the preamplifier 2 and is also inputted to a control terminal of a pre-filter 4 of a poststage to shift the cutoff frequency of the pre-filter to be lower than the cutoff frequency set under sufficient illumination. Signals passed through the pre-filter 4 are converted to digital signals in an A/D converter 5 and then, image compression for transmission is executed in the compression encoder 6.
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申请公布号 |
JP2000224471(A) |
申请公布日期 |
2000.08.11 |
申请号 |
JP19990025081 |
申请日期 |
1999.02.02 |
申请人 |
SHARP CORP |
发明人 |
ITO SEIICHIRO;TOMIOKA MASAO |
分类号 |
H04N5/14;H04N5/243;(IPC1-7):H04N5/243 |
主分类号 |
H04N5/14 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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