A 5 kHz channelling VHF linear modulation receiver for volume production
Stuart Whittle · 1995
Increased demand for spectrum has led the regulatory authorities to encourage the adoption of voice and data systems using 5 kHz channelling. In the USA, 200 duplex channels in the 220 to 222 MHz band released by the FCC are now in use. In the UK, a regulatory specification is published by the Radiocommunications Agency and trials have been carried out in the 70 MHz, 160 MHz and 220 MHz bands. Manufacturers are now using digital signal processing (DSP) in low-cost, flexible mobile transceivers. DSP is applicable both for linear receivers and for transmitters such as those using a Cartesian loop. Private Mobile Radio (PMR) equipment operating with 5 kHz channelling is now manufactured in volume and provides both excellent analogue voice quality and 14.4 kb/s digital capability for data or digital voice applications in both static and fading environments.