In March 1998, WFAA-TV in Dallas became the first
television station in the United States to venture into the future of
digital broadcasting. But as the broadcast signal went into the
airwaves, medical telemetry units on the 13th floor at nearby Webb
Roberts Hospital at Baylor University Medical Center went blank.
It was 24 hours before engineers at the television station and Baylor
put 2 and 2 together to figure out that the heart monitors were on the
same frequency as the station's new signal. There was a good chance
that theirs was not the only conflict. As a result, the US Food and
Drug Administration (FDA) sent out an advisory warning hospitals and
healthcare providers of the potential conflict. The situation, the
agency warned, could occur in other parts of the country because of a
quirk in the way television channels are assigned.
Several years ago, the Federal Communications Commission (FCC) decided
to allow medical telemetry devices to use part of the broadcast
spectrum that was also used by television stations. The medical
telemetry units were assigned a television channel that was not being
used in a particular area. However, the agency warned that television
stations had priority and medical devices had to be able to tolerate
television signal interference. Putting the 2 different kinds of users
on separate channels originally alleviated the problem.
But the advent of digital broadcasting forced the FCC to give stations
an additional channel during the transition to the newer form of
broadcasting. The
© 1998 American Heart Association, Inc.
Cardiovascular News
High-Definition Television and Telemetry