Updated 10/30/2025 by W1DRF

With Digital Signal Processing, you can manipulate signals after they have been converted from analog voltages and currents into digital form -- i.e., as numbers.  Normal analog operations of filtering, mixing, and signal detection all have their parallels in the DSP world.  Because the cost of complex digital processing is very low, DSP is often the preferred way to build high-performance communications systems, and it allows for a low-distortion modification of analog waveforms that would require a lot of expensive and complex circuitry to do using hardware.

DSP, in the RF world, is commonly performed using a device called an FPGA, which is a programmable IC, or integrated circuit, that can perform real time mathematical operations on signals at incredibly high speed. FPGAs are designed for repetitive processes that don't require a lot of variables to complete a task, making them perfect high speed data processors for digitizing and performing DSP operations on analog signals, and also for generating RF data to be sent over the air. Your common WiFi Router contains an FPGA to send and recieve data in the GHz frequency range at rates of millions of bits, despite often costing much less than 50 dollars. Most telephone calls also use DSP to improve the audio quality between links and eliminate sources of background noise.

• Signals, Samples and Stuff: A DSP Tutorial - Part 1
  QEX, March 1998, pp. 3-16
  What's DSP all about?
• Signals, Samples and Stuff: A DSP Tutorial - Part 2
  QEX, May 1998, pp. 22-37
  Let's look inside an IF-DSP transceiver.
• Signals, Samples and Stuff: A DSP Tutorial - Part 3
  QEX, July 1998, pp. 13-27
  Advances DSP techniques.
• Signals, Samples and Stuff: A DSP Tutorial - Part 4
  QEX, September 1998, pp. 19-29
  Conclusion.
• Digital Signal Processing for the Experimenter
  QST November 1984, pp22-27
  Flash - A/D-igital data stream replaces an analog signal. DAC puts it back again!
• An Introduction to Digital Signal Processing
  QST July 1991, pp35-37
  DSP makes headlines even in an age where digital seems to be applied to just about everything electronic - and now it's part of Amateur Radio.
• Digital Signal Processing and GNU Radio Companion, QEX, July/August 2014, pp. 41-46
  
• Digital Signal Processing (DSP) Projects: Examples of GNU Radio and GRC Functionality, QEX, September/October 2014, pp. 25-30.
  

•  "The Scientist & Engineer's Guide to Digital Signal Processing", by Steven W. Smith. Download individual chapters or the entire book absolutely free!