besides the fact that they amplify videos signals and not sound signals
2007-06-30 06:02:57 · 4 answers · asked by macgyver 1 in Science & Mathematics ➔ Engineering
and i am talking about the audio amplifiers that drive speakers
2007-06-30 13:09:40 · update #1
video amps have a minimum bandwidth of 30 Hz to 6 MHz, more is decidedly better. the output of a video amp designed to drive 75 ohm impedance load. professional design amps have a 75 ohm build out resistance in series with each load. To drive other video equipment, the nominal signal output is 1 vpp (1.4 vpp if you measure to the sync tip), or double that because of the buildout resistor. video amps can also incorporate a dc restorer circuit so that the sync pulse is always negative dc and video is positive dc as defined by NTSC. the dc reference can otherwise be lost if a capacitor is used in series with the input. modern equiment that is sensitive to polarity usually incorporates a clamp circuit, so video amps will generally not need dc restoration.
When built as a "distribution amp" (1 in 4 out, for example) the input must present a 75 ohm load. many times the input loops through and the load is a removable 75 ohm resistor, which allows the incoming video to be cabled to other devices in the loop. The actual amp impedence then bridges or is high impedence, typically 1000 ohms or more. The amp is not unity gain, but rather has a voltage gain determined by the buildout resistors on the output so that the output voltage is identical to the input.
2007-06-30 09:24:20 · answer #1 · answered by lare 7 · 0⤊ 0⤋
In general, not much other than bandwidth, though it depends on the application, e.g, is the audio amp a preamp or is it going to drive speakers? How much distortion is allowed? Does the video amp drive a long cable or many inputs?
But you won't generally use the same amp for audio that you would for video, no matter what the application. But if you're just experimenting, there are plenty of opamps than can do a so-so job at both.
2007-06-30 13:58:11 · answer #2 · answered by Gary H 6 · 0⤊ 0⤋
Video refers very often to DC coupled amps, becuase they had to be DC coupled in the old TV.s The term Video has also become synonomous with "high speed". 6MHz at one time was high speed. The terms last for decades.
The 741 op amp is still billed as a "high performance op amp". Well, it was, in 1973. Much better things have come along.
2007-07-01 00:07:40 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Both are amplifiers, the principle is the same.
2007-06-30 17:46:53 · answer #4 · answered by jaime r 4 · 0⤊ 0⤋