The R8B communications receiver is a microprocessor controlled, synthesized, all mode, world band receiver with continuous coverage capability from 100 through 30,000 kHz. The receiver offers excellent sensitivity, selectivity, high dynamic range and offers features for the most demanding shortwave reception. Conveniently located front panel controls allow for rapid operator programming and ease of use. Operating mode and corresponding bandwidth are quickly selected by front panel but- tons. The selectable AC input allows for operation around the world. In addition, a DC input is provided for mobile operation. A High-Q, 8-pole, electronically switched IF filter provides a range of five commonly used bandwidths. These band- widths are automatically selected by mode, however any bandwidth may be selected at the touch of a button. The front panel liquid crystal display provides visual feed- back to the operator of the current status of the receiver. The seven digit frequency display allows tuning resolution to 10 Hz accuracy. In the AM mode, a selectable sideband synchronous detector (SYNCHRO) allows for enhanced reception by eliminating or reducing distortion due to fading signals and allowing the passband to be shifted toward one sideband, to reject interference, without causing audio A PASSBAND OFFSET control also aids in reducing or eliminating interfering signals by electronically shifting the receiver's IF frequencies without disturbing the operating frequency. This action allows the operator to electronically move interfering signals out of the receiver’s pass- band thus utilizing the high degree of selectivity provided by the High-Q, 8-pole IF filter. Other built-in reception aids include selectable AGC speed, dual antenna inputs, noise blanker(NB), RF preamplifier for enhancing weak signals, RF attenuator for further improvement of strong signal handling capabilities, ad- justable RF gain, NOTCH, TONE and SQUELCH controls. Two independent, real time clocks provide a local and alternative time selection. Also provided is a two event timer. A programmable memory area allows for 1000 independent receive memories. In addition, these memories are stored in a battery backed-up memory chip to ensure memory retention during power line failure. Any of these memories may be altered by the operator and re-stored. These memory channels may be accessed manually or by various scanning methods. Finally, a built-in RS-232 compatible interface allows complete digital control of the receiver including memory and scanning functions.