Principles of design of battery operated frequency modulation receivers

The special requirements of battery operated receivers generally include low running cost and the maintenance of adequate performance at reduced battery voltages. The designer, in attempting to achieve these results, is faced with several major problems not encountered in the design of the mains operated counterpart arising from the inherent features of the limited range of 1.4 V filament valves. Following a discussion of the above, principles and design of the individual stages of an a.m./f.m. receiver are dealt with, including the mixer stage, i.f. amplifier and demodulator circuit. The remainder of the receiver follows standard practice and receives only a qualitative treatment.