What is Digital Signal Processing?

Initially, when DSP or Digital Signal Processing was introduced over thirty years ago, it involved standalone processing. A single micro-controller handled all the parameters for processing the analog signal and transforming it to its digital value. Evolution in this area has introduced multicore processing elements that now extend the DSP’s range of applications.

Simultaneously, evolvement of software development tools for the DSP now allows expansion for accommodating diverse programmers. Therefore, on one hand you can have voice and image recognition with small, low power, but smart devices, while on the other, it is possible to have real-time data analytics with the multiple core high-performance compute platforms. This way, DSPs offer nearly endless opportunities for achieving low-power processing efficiencies.

Although initial DSPs processed only audio, engineers quickly adapted DSP technology for a wide variety of applications. Today, DSPs are available as standalone or as part of an SoC or System-on-Chip offering full software programmability including all the benefits of software-based products.

DSPs take already digitized signals from the real world, such as audio, video, pressure, temperature or position for further mathematical manipulations. Engineers design DSPs for performing quick mathematical operations such as add, subtract, multiply and divide.

This processing of the signals enables displaying, analyzing or converting information to a signal of another type to be useful. In the real world, several analog products are available to detect and manipulate signals such as pressure, temperature, light or sound. These signals are then passed on to converters such as ADCs or Analog to Digital Converters, which transform the analog signals into a digital format of 1’s and 0’s.

The DSP takes over this stream of digitized information and processes it further. The processed digital information goes back for use in the real world. The DSP does this in one of two ways. It feeds the information in the digital format to instruments capable of handling it. Where that is not possible, the digital signal passes through a second converter or DAC, the Digital to Analog Converter and this converts the digital signal to analog. All this happens at very high speeds.

An MP3 player is a very simple illustration of the concept of DSP. The analog audio, during the recording phase, passes through a receiver containing a microphone and an amplifier. An ADC then converts this analog signal into digital information, before passing it over to a DSP. The DSP processes the digital signal further as defined by its internal algorithm and encodes it as MP3, before saving the file to memory.

While playing back the recorded information, the DSP decodes the file from memory and a DAC converts the digital signal to an analog form. That makes it suitable to output the signal through an amplifier and speaker system. If necessary, the DSP handles other functions such as level control and equalization including user interfacing.

A computer can also use information from a DSP. The computer can use this information to control security, home theater systems, telephones and for compressing video. Compressed signals are more efficient when transmitting. Additionally, the computer can easily manipulate or enhance the signals to improve their quality.