Tuning Indicators and Circuits for Frequency-Modulation Receivers

Frequency modulation provides good reception, but requires operation at resonance. The circuits described in these pages are applicable to standard receivers and provide effective means for accurate tuning. Some of these circuits include additional diodes, triodes, and combinations of diodes and triodes to produce sharp determination of the discriminator crossover point. A novel tuning eye employing two grids is suggested for a simplified tuning indicator.