Codan Radio P25 Training Guide - Manual (Page 53)

P25 RADIO SYSTEMS | TRAINING GUIDE
Chapter 3: P25 Technical Information Page 45
Audio Frequency Measurements
FM audio frequency measurement is done with a standard frequency counter. C4FM audio frequency
measurements cannot be accurately measured.
RF Power Measurements (FM and C4FM)
RF Power measurements for Digital C4FM and Analog FM can be made with a standard peak detecting
power meter. C4FM digital transmissions are the same as FM transmission in that they are of constant
amplitude.
Analog FM Modulation Accuracy
A deviation meter is used to measure Analog FM Modulation Accuracy. The deviation meter monitors
peak carrier movement above and below the carrier center frequency and displays the average offset.
Various IF Bandwidth fi lters are required to ensure accurate measurements.
Digital Modulation Accuracy (Modulation Fidelity)
Modulation fi delity is the degree of accuracy between the actual modulation and the ideal theoretical
modulation.
Modulation fi delity is determined by taking deviation measurements synchronously with the decoded
symbol clock and averages the measurements over a group of symbols to calculate a percentage
of error. The measured deviation is only important at symbol time. This test requires specifi c test
patterns to be generated from the transmitter.
Common Air Interface Protocol Testing
CAI Protocol testing requires the ability to decode and encode the 9600 baud data to and from voice and
data information. The decoding and encoding capability allows for verifi cation of the radio programming,
testing emergency conditions, talk groups, and repeater accessing codes off the air.