What is amplitude shift key (ASK)?

Question

What is amplitude shift key (ASK)? And how does it work? What is an ASK tranceiver and receiver circuit?

Answer 1

That above answer is not correct, it confuses ASK with OOK. OOK is when you turn the signal on and off, if the signal is present thats a binary '1'.

Assuming you know a little about why you want to modulate a carrier, ASK is when you take a sine wave and vary its amplitude (the peak to valley distance) while holding everything else constant. The amount of amplitude variation, and the frequency of amplitude variation convey the data of another analog waveform.

A demodulator (reciever non synchronous) is a simple low pass filter and a bridge rectifier. Which results in an envlope detector.

The easiest way to modulate ASK is with an IQ modulator.

Answer 2

Amplitude Shift Keying Circuit

Answer 3

The above answer is tecnically correct, but OOK is a special case of ASK, so the first answer is also correct. The term "keying" comes from the old days when signals were sent by Morse code using a telegraph key. When the key was pressed, it caused a shift in the carrier signal (usually a sine wave). If the shift is in the amplitude of the signal, that is ASK: amplitude shift keying, If the shift is in the frequency of the signal then it is FSK, or frequency shift keying. Since one level of amplifude in ASK could be zero, this then becomes OOK (on-off keying).

Answer 4

Wikipedia is your friend:
Amplitude-shift keying (ASK) is a form of modulation which represents digital data as variations in the amplitude of a carrier wave.

The amplitude of an analog carrier signal varies in accordance with the bit stream (modulating signal), keeping frequency and phase constant. The level of amplitude can be used to represent binary logic 0s and 1s. We can think of a carrier signal as an ON or OFF switch. In the modulated signal, logic 0 is represented by the absence of a carrier, thus giving OFF/ON keying operation and hence the name given....