I am often asked to explain why FPGAs are so often linked with the term DSP. Very often it turns out that the person asking the question is confused by the fact that the abbreviation "DSP" has two meanings -- "Digital Signal Processing" (the act itself) and "Digital Signal Processor" (a special-purpose device intended to perform the act of digital signal processing).
The big point to wrap one's brain around is that you don't actually need a digital signal processor to perform digital signal processing (this statement assumes we all agree on what we mean by "digital signal processor," of course).
Analog signal processing (ASP)
Before we leap into the concept of digital signal processing, let's first remind ourselves that the real world is predominantly an analog realm. We also need to remind ourselves that we can create electronic circuits and systems that operate in an analog or digital fashion.
In the context of electronics, an analog device or system is one that uses continuously variable signals to represent information for input, processing, output, and so forth. On this basis, analog signal processing (ASP) involves the processing of signals in the analog domain. Consider the simple ASP system shown in the following block diagram:
Simple analog signal processing (ASP) scenario.
Here we see a sine wave from a guitar being fed into a voltage-controlled amplifier. The amount of amplification is controlled by a lower frequency sine wave coming from a signal generator.
In the early days of electronics, systems were predominantly analog in nature. This was due to a number of reasons, including the fact that electronic components used to be expensive and you can do a lot of processing with relatively few components in the analog domain, so long as that processing is relatively simple. Another consideration is that digital concepts were not well understood in the early days of electronics.
Next page >