What would happen if a digital signal is fed to an Analog to Digital converter?

Question

I would like to know what would happen to a digital signal if it is sent to an analog to digital converter? Will the signal pass through unchanged or will there be any changes in the signal?

Answer 1

It will be digitized, subject to the voltage limits, precision and frequency limitations of the A2D converter.



For example, if your A2D acquires 5K samples/second over a voltage range from 0 to 4 volts with a precision of 8 bits, and you feed in a digital signal that varies between 0.5 and 2.5 volts, and consists of pulses that are 1 ms wide, at a repetition rate of 500 pulses/s, the A2D output might look like this (in decimal):



31, 32, 31, 30, 32, 90, 164, 160, 162, 161, 104, 29, 31, 30, 32, 95, 163, ...



If you plot the numbers on a graph you'll see a rough reconstruction of the original wave.



In practice, digitizing signals with sharp edges (such a digital signals, but also many analog signals from sensors) requires careful attention to the frequency content of the signal. This is normally done by applying a low-pass filter to the signal before digitization.

Answer 2

It will be sampled as an analog signal and the precise value will be scaled accordingly. For example, a TTL logic '1' will usually be somewhere around 3.5V. If you feed that into an ADC that counts in 1mV units you'll get a result of 3500. If you conencted it to a 5V supply the ADC would then read 5000 even though a TTL input would still read both as 1.

Answer 3

on your hyperlink, for enter it states: Converter-container Antenna Inputs i. smart Antenna forty. The NPRM proposed that the sole enter to the converter container would be for an exterior antenna. The NPRM reported that “[a] single enter (form F connector) ensures that purely an antenna could be linked to eligible packing containers as a result ensuring use of such packing containers as for over-the-air television reception purely.”[ seventy 8 ] including a QAM tuner is going previous the undemanding standards to obtain off-the-air television.