AM Broadcast and Receiver standards-Towards Opening a Dialogue

This paper attempts to open a dialogue between broadcasters and receiver manufacturers regarding standardization of transmitter and receiver frequency response to increase consumer satisfaction with AM. The problems, politics, and economics of the broadcasters are discussed. A family of pre-emphasis curves and a single “quasi-wideband” de-emphasis curve are presented. The authors believe these to be the most effective compromise between the “wideband” and “narrowband” camps. These curves permit the bandwidth of the receiver to be substantially widened without introduction of unpleasant stridency or other undesirable effects. Simultaneously, they are highly effective in improving the perceived high frequency response of existing narrowband radios. Together, the pre-emphasis and de-emphasis provide “quasi-high-fi” audio which can sound very similar to FM to the consumer listening in the car.