| 摘要 |
BROADBAND. HIGH SPEED VIDEO AMPLIFIER A broadband, high speed, signal inverting video amplifier (10) comprises a generally conventional, main cascode amplifier (20) and first and second current boosting cascode amplifiers means (14, 16) which are capacitively (CB3, CB2) coupled to the main cascode amplifier (20). The first current boosting amplifier (14) provides a positive current spike (62) in response to an input video signal (22) abruptly decreasing, the positive current spike (62) provided thereby being fed into the main cascode amplifier (20) in a manner causing the current spike (62) to be added to current (I) through the main amplifier (20) when the amplified video signal (22) goes positive. The second current boosting amplifier (16) provides a negative current spike (64) in response to the input video signal abruptly increasing, the negative current spike (64) provided thereby being fed into the main cascode amplifier (20) in a manner causing the such current spike to be subtracted from the current (I) through the main amplifier (20) when the amplified video signal (22) goes negative. The positive and negative spikes (62, 64) cause the amplified output video signal (42) to have rise and fall times to be less than about 3.5 nanoseconds at loads (C TOTAL) of at least about 25 pf at peak-to-peak output voltages of at least about 40 volts and to be no more than about 1.8 nanoseconds at about 20 volts peak-to-peak for a load of (C TOTAL) about 14.5 pf. |
