pite Posted August 20, 2011 Share Posted August 20, 2011 I had a VIzio LCD that would turn itself off on the video while the audio continued on. I figured it was the power board with a problem. It was under warranty, they sent a guy out that couldn't fix it. I boxed it up and took it back to the store for a swap with a different brand unit. All good with that one, Philips. Great...No more worries I guess with a new unit and a different brand...[] Quote Link to comment Share on other sites More sharing options...
JJkizak Posted August 20, 2011 Share Posted August 20, 2011 Pite: If the waveform is rounded that means there is less high frequency information in the waveform. The sharper and squarer it is the more high frequency info is in the waveform. The more rounded the waveform the more distortion it does contain. That's one reason why the "testers" used square waves to test high end audio equipment. The more the square wave is distorted the worse the rating of the amplifier usually at the highest power output. JJK Quote Link to comment Share on other sites More sharing options...
pite Posted August 20, 2011 Share Posted August 20, 2011 Pite: If the waveform is rounded that means there is less high frequency information in the waveform. The sharper and squarer it is the more high frequency info is in the waveform. The more rounded the waveform the more distortion it does contain. That's one reason why the "testers" used square waves to test high end audio equipment. The more the square wave is distorted the worse the rating of the amplifier usually at the highest power output. JJK hmmm...I was refering to the input side... In Class A the output stage will conduct through 360 degree of input cycle...The pasted link expains in details about different amplifier Class, their benefits, shortcomings, and tradeoffs... http://sound.westhost.com/class-a.htm. Not sure, but you might be refering to Class D amplifiers...They are good for Car Stereo application (being low on power budget) in need of efficient amplifier or Sub-Woofer application required limited frequency amplification... There are only handful of manufacturer who has honed Class D amplfier technology to use for full spectrum of frequency, but at a premium price... hint - audio system in high end [au] !!! With Class D amplifier one can have analog or digital input that can be fed to switching PWM section. Subsequently, it's fed to Low Pass Filter - LPF. However, in most case, the PWM switching stage itself becomes the source of distortion/limitation (THD - Total Harmonic Distortion). e.g. Pulse Width Error / Quantization Error, Non-Linearity in PWM signal, Timing Errors added by Gate Drivers, Unwanted Charecterisitics in Switching Devices, Parasatic components causing ringing, etc... [8-|] Quote Link to comment Share on other sites More sharing options...
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