| 摘要 |
PROBLEM TO BE SOLVED: To provide compensation characteristics provided with flat frequency characteristics over the entire area by correcting the levels of low band and high band components and performing amplification by a fixed gain over the entire frequencies so as to turn the low band component to a prescribed amplitude thereafter. SOLUTION: A video signal transmitter 1 inserts low band and high band reference signals S1 and Sh by an adder 2 during the period not obstructing a video screen. This cable compensation device 3 receives them in an amplifier 4 for (f) characteristic adjustment, detects the reference signals S1 and Sh in S1 and Sh amplitude detectors 5 and 6, inputs them to a comparator 8 and compares the signal levels. A compared result is fed back to the amplifier 4 for the (f) characteristic adjustment and a compensation amount is increased/decreased. Then, the reference signals S1 are sampled from the output of the amplifier 4 for the (f) characteristic adjustment by the amplifier for gain adjustment, compared with a reference level VREF by the comparator 11 and fed back to the gain adjustment amplifier and adjustment is performed so as to turn the difference to '0'. Thus, the compensation characteristics provided with the flat frequency characteristics from a low band to a high band are obtained. |
