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As already said an atttenuator reduce the amplitude of a signal by a given amount. f.i if you have a signal of amplitude 10 dBm at the input of a 3 dB attenuator, at it's output you will have 10-3=7 dBm
From limiter and clipper there should be a slight difference. They could be either active or passive.
A limiter as the word says, limit the signal level at a wanted value. Usually it's limiting property is specified as a power. If, f.i. you have a 4 dBm limiter, if the input signal is below 4 dBm it will pass as it is, otherwise is's amplitude will be limited to 4 dBm. Usually real the behaviour is quite soft, starting to compress a little bit before 4 dBm and increasing it's attenuation while the input signal is increasing in amplitude.
A clipper is usually defined in voltage. The behviour is instead quite hard. If f.i. you have a 5 V clipper applied to a 8 V sinewave you will have a sinewave in which the maximum amplitude will be 5V, that means for a certain amount of time you will see a constant value.
Then we have slicers ( precision comparators for analog data streams which produce logic levels out and very little skew in rise/fall time and very little asymmetry from sine to square wave)
Most slicers use voltage drivers for single ended or differential output, and faster ECL types using current mode drivers with differential outputs.
Then we have comparators usually referring to 300kHz max ~10MHz type applications, which span a wide range of inputs, output types and speeds with variable or fixed thresholds like Op Amps but intended as fast open loop gain differential amplifiers to limit the output to the supply rails.
An RF limiter is quite different in speed than an Audio Class E amplifier, but both drive the output swing to the limit determined by Output stage type.
RF limiters are for FM or PM type demodulators using in PLL's certain radio's etc. etc.
Clippers prevent over-voltage or are over-driven analog amplifiers.
For audio signals:
1) Do you want to attenuate loud and not loud signals?
2) Do you want to make acid rock limiting or clipping distortion?
3) Do you want to avoid distortion by compressing high levels with low distortion?
For audio signals:
1) Do you want to attenuate loud and not loud signals?
2) Do you want to make acid rock limiting or clipping distortion?
3) Do you want to avoid distortion by compressing high levels with low distortion?
In "the good old days" we used a transistor amplifier driving a rectifier that controlled the resistance of a Jfet as the attenuator.
Then we replaced the transistor with an opamp.
There were "compander ICs" (compressor or expandor) available like Signetics (bought later by Philips) NE570, NE571 and NE572. Read about compandors in Philips applications note AN176.
When I worked with telephone and video conferencing the digital compressor attack time was way too slow like old radio and TV audio where there was a blast of loud audio before the compressor "woke up".
The original post didn't clarify that you are asking about audio signals.
It's simple to make a peak level limiter with fast (< 1 ms) attack and moderate (several 100 ms) release. It should have no audible effect as long as it's not reducing the gain and sounds much better than an overloaded amplifier. It's also an effective means to protect speakers, particularly tweeters.
If the limiter is built into the power amplifier, it can derive the threshold from the DC supply.
Many radio stations turn up the volume too much then the compressor reduces it during the bass beats which modulates the background music and it sounds awful.
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