Digital signal processing

A new and fast advancing communications technique, digital signal processing (DSP), promises to revolutionize voice, digital communities, and image communications.In the analog modes, DSP works by converting received voice or video signal input into the digital data by means of analog-to-digital (A/D) converter. The digital signal can be processed and can be reconverted back to original voice or video by means a D/A converter.

                                                                          Figure--Digital signal processing.

In digital modes, A/D and D/A conversion is not essential, but DSP can be still used to clean up the signal. This decreases the number of errors.It is in digital part of DSP circuit that the signal enhancement  occurs. Digital signals have a finite number of well defined states. It is a simple to process a signal of this kind than to process an analog signal, which has a infinite theoretically number of possible states. The DSP circuit gets rid of confusion among digital states. The result is an output which is essentially free from interference.

Digital signal processors are available from various commercial sources. They can be installed in the present communications receivers.The benefits of DSP are improved signal-to-noise ratio, superior intelligibility, and improved fidelity or image clarity. Addition to this DSP can make a AM, CW, or SSB receiver less susceptible to interference from atmospheric noise and ignition noise. This is as a digital signal is as different from noise as a watermelon is from the apple.