What is the use of modulator and demodulator in transponder?
Answers
Answered by
0
The transponder works in PCM (pulse code modulation): how does it work in the transponder? I can find explanation of what PCM is, but not if the signal sent from the transponder antenna is digital or analog, and I do not understand which are the advantages of using PCM.
Type of modulation in term of ITU classification
In the context of radiocommunication, PCM is more accurately described as ITU class A1D:
As bits are transmitted one by one, the carrier is sent or interrupted, according to the bit value.
Phase and frequency are maintained constant.
It's like morse at high speed. It can also be seen as amplitude modulation (either the carrier has its maximum amplitude, or a null amplitude).
This form of modulation is also commonly known as binary amplitude shift keying (BASK) or on-off keying (OOK), and is a variant of pulse amplitude modulation (PAM). See this page for more details. Data communication, on the borders of multiple engineering disciplines is quite generous with synonyms.
There is a common confusion between A1D modulation and the PCM codec used in the context of audio files. This PCM is a near-lossless codec (coder-decoder) used in Compact Disc and legacy .wav files, and has nothing to do with a modulation.
Type of modulation in term of ITU classification
In the context of radiocommunication, PCM is more accurately described as ITU class A1D:
As bits are transmitted one by one, the carrier is sent or interrupted, according to the bit value.
Phase and frequency are maintained constant.
It's like morse at high speed. It can also be seen as amplitude modulation (either the carrier has its maximum amplitude, or a null amplitude).
This form of modulation is also commonly known as binary amplitude shift keying (BASK) or on-off keying (OOK), and is a variant of pulse amplitude modulation (PAM). See this page for more details. Data communication, on the borders of multiple engineering disciplines is quite generous with synonyms.
There is a common confusion between A1D modulation and the PCM codec used in the context of audio files. This PCM is a near-lossless codec (coder-decoder) used in Compact Disc and legacy .wav files, and has nothing to do with a modulation.
Similar questions