Participant Testing of AM Broadcast Transmission Bandwidth and Audio Performance Measurements of Broadcast AM Receivers

摘要

In late 2004 the NRSC's AM Broadcast Subcommittee formed the AM Study Task Group (AMSTG) to determine whether consumers would reliably perceive audio quality differences of AM transmissions recorded through commercially available receivers at bandwidths lower than 10 kHz. A study was conducted to document the audio performance of a large number of AM receivers and evaluate three prototypical receivers in a consumer-based listening test. Results suggest that for compressed audio that masks background noise (that is, rock music), participants heard little difference between 7 and 10 kHz, regardless of adjacent channel interference conditions. However, for less compressed audio that does not mask noise (that is, speech) larger differences were heard, depending on interference conditions. Results suggest that in general consumers preferred lower transmission bandwidths to higher trans mission bandwidths in real-world noise conditions.