Problem: A High-Frequency Analog Signal Cannot Be Accurately; Recreated By A/D And D/A Conversion. (2 - JVC RX-D702 Technical Manual

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Problem: A high-frequency analog signal cannot be accurately recreated by A/D and D/A conversion. (2)
Problem: A high-frequency analog signal cannot be accurately recreated by A/D and D/A conversion. (2)
RX-D702
The "sampling theorem" says that, if the sampling frequency is more than twice as high as
the maximum frequency of original signal, then the original signal can be retrieved by A/D
and D/A conversion. With CDs, the sampling frequency is 44.1kHz, meaning the maximum
frequency is band-limited to 22.05kHz. Therefore, the information on the waveform for over-
22.05kHz frequencies is not transmitted.
Unless it's sinusoidal, a signal contains multiple high-order harmonics. So does a square
wave. If the input is a 1kHz square wave signal, it retains its shape because much of the
information on the waveform for harmonics is retained after the A/D and D/A conversion.
But if the input is a square wave of a high frequency, the converted signal presents
a rounded shape because of the absence of information on high frequencies.
A/D and D/A Conversion in Frequency Domain
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