Is it true that FPGAs and DSPs are widely used for modulation and demodulation of signals?
It is true, that &quot;FPGAs and DSPs are widely used for modulation and demodulation of signals in communications&quot;. That means, that the data link level in a canonical OSI model is implemented purely in hardware or with a strong hardware support. The reason for this is that modern high-speed communications require the processing speed, that a pure software implementation can not support.
Here you have to take into account, that, backed up by wikipedia, &quot;a digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing&quot;. That means that a computation-intensive operations are performed with the help of specialized hardware as a part of a DSP (mainly, hardware multiplication).
An obvious example is GbE, where you have to transmit 1 billion bits per second. And even for that, modern FPGAs include dedicated hardware modules called transceivers (an example for Intel).
In a simpler cases (i.e. slower interfaces), the hardware implementation of a low-level modulation-demodulation is still much preferred. The reason for that is that to keep the link up you will need to serve it constantly, which can potentially occupy the most of the processor clocks, when implemented as a software.
It follows, that the statement &quot;most of the digital modulations and signal processing nowadays are done via software&quot; can be considered false.