Home |
Search |
Today's Posts |
#161
|
|||
|
|||
Audio amplifier design trivial?
On Thu, 30 Oct 2003 18:22:36 +0100, Sander deWaal
wrote: BTW, I'm curious as to how the video sync pulses came into the amplifier circuit. Was it just strong radiation of harmonics and detection by the amplifier, or was it pure superimposition on the supply lines? Hey Sander, nice to see you back! How have you been? -- The Devil |
#162
|
|||
|
|||
Audio amplifier design trivial?
The Stainless Steel Boob Orchestra said:
Hey Sander, nice to see you back! How have you been? Well, a lot has happened, but I'm doing much better than 2 years ago. A story too long to tell here, but feel free to drop me a personal note, the e-mail return address is valid. -- Sander deWaal Vacuum Audio Consultancy |
#163
|
|||
|
|||
Audio amplifier design trivial?
Sander deWaal wrote in message
BTW, I'm curious as to how the video sync pulses came into the amplifier circuit. Was it just strong radiation of harmonics and detection by the amplifier, or was it pure superimposition on the supply lines? The RFI came in the phono input. The turntable leads acted as an antenna. |
#164
|
|||
|
|||
Audio amplifier design trivial?
"Robert Morein" wrote in message
Since the RF amplifier is not baseband, distortion in the signal does not appear directly in the modulated signal. Interference beats do appear on the video (on the TV screen). If one takes a signal generator and inserts an interfering signal (sinewave) on an RF line, it will cause wavey lines to appear on video. The the threshold of visibility is -60 dB. In audio terms, that would be 0.01% distortion. The threshold of interference visibility for video, seems to be about the same as the threshold of distortion audibility for audio. Even with simple class AB designs, very high power output can be obtained with a small component count, since the distortion products are broadband and not concentrated around the carrier. By contrast, since the audio amplifier is a baseband instrument, the distortion products are largely concentrated in the passband. Audio amplifiers and CATV amplifiers are both broadband products. They both face the same distortion challenges. A RF amplifier tested with a signal of two sinewaves, say at 400 MHz and 500 MHz, will generate exactly the same kind of second order and third order products as an audio amplifier with a signal of 400 Hz and 500 Hz. For example, the audio amplifier will generate sum and difference distortion products of 100 Hz and 900 Hz. The RF amplifier will gernerate sum and difference products of 100 MHz and 900 MHz. (And so on, for all the other second and third order products.) Bob Stanton |
#165
|
|||
|
|||
Audio amplifier design trivial?
"Bob-Stanton" wrote in message
om The threshold of visibility is -60 dB. In audio terms, that would be 0.01% distortion. -60 dB is 0.1% The threshold of interference visibility for video, seems to be about the same as the threshold of distortion audibility for audio. Yes, even under the most ideal conditions, audibility of nonlinear distortion seems to go away someplace around or below 0.1%. Under non-ideal conditions, several percent nonlinear distortion can be missed. |
#166
|
|||
|
|||
Audio amplifier design trivial?
"Arny Krueger" wrote in message ...
"Bob-Stanton" wrote in message om The threshold of visibility is -60 dB. In audio terms, that would be 0.01% distortion. -60 dB is 0.1% Yes, I agree. My mistake -20 dB = 10% distortion -40 dB = 1% distortion -60 dB = 0.1% distortion It just proves the old saying: "There are three kinds of people in this world. Those who can do math and those who can't." :-) Bob Stanton |
#167
|
|||
|
|||
Bad scientist ALERT!!!
"Robert Morein" wrote in message ... "Sockpuppet Yustabe" wrote in message ... "Robert Morein" wrote in message ... Snip How big was that telescope Bob? |
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Car audio amplifier with digital audio inputs | Car Audio | |||
Amplifier recommendations / MtX vs. JL Audio vs. other? | Car Audio | |||
rec.audio.car FAQ (Part 2/5) | Car Audio | |||
rec.audio.car FAQ (Part 1/5) | Car Audio | |||
FS: SOUNDSTREAM CLOSEOUTS AND MORE!! | Car Audio |