Philips IntelliVue Quick Reference Service Manual page 31

3. Remove the battery from the problem transmitter
and monitor the RF History Strip for that channel.
a. On-Channel or Narrowband Interference - is
defined as an interference source that
occupies the same bandwidth as the
transmitter and only interferes with one
channel or two frequency adjacent channels.
It is likely that the channel is set to the same frequency as
another telemetry unit. To correct this, change to a clear
frequency or remove the interference source. Be certain
and check for M2600A Telemetry Channels, M1403A
Digital Telemetry channels, 78100/101A Analog Telemetry
channels, and for M1310A and 80240A Fetal Telemetry
channels. Also check for other radio devices, such as
walkie-talkies, paging systems, ambulance systems, etc.
b. Broadband Noise - a broadband interference
source occupies the bandwidth of many channels
causing degradation of the carrier-to-noise ratio
(CNR) on all of the telemetry channels for as long
as it is present. This results in an increase in
dropouts and TEL CANNOT ANALYZE"/
"INTERFERENCE INOPs on all of the channels.
The system has quiet and noisy periods. When the
noise source is on, the system is noisy. When the
source is off, the system performs well. To
eliminate the problem, do the following:
– Troubleshoot the problem as it is occurring.
Use the RF History Strips and information
from users to determine if there is a pattern,
when the episodes occur, and how long they
last. If there is a pattern, (e.g. every morning
between 6 and 8am, the first weekend of the
month etc.) try to predict when the next
occurrence will happen and prepare to
troubleshoot.
RF Troubleshooting Procedures
31