COMTEK M-175 - Manual (Page 12)

Page 10
M-175
LETTER CHANNELS
(72-76 MHz)
CHANNEL FREQUENCY
91
95
98
00 A 72.1 MHz
E 72.9 MHz
H 75.9 MHz
J 75.3 MHz
GROUP 1
CHANNEL FREQUENCY
92
97
99 B 72.3 MHz
G 75.7 MHz
I 74.7 MHz
CHANNEL FREQUENCY
93
96 C 72.5 MHz
F 75.5 MHz
GROUP 2
GROUP 3
CHANNEL FREQUENCY
91
92
93
94
95
96
97
98
99
00 A 72.1 MHz
B 72.3 MHz
C 72.5 MHz
D 72.7 MHz
E 72.9 MHz
F 75.5 MHz
G 75.7 MHz
H 75.9 MHz
I 74.7 MHz
J 75.3 MHz
Standard
Non-Companded
Channels
(For PR-72b and PR-75)
Note: Although the same frequencies appear in the companded and
non-companded frequency charts, non-companded channels should not
be used with companded receivers.
In order to accommodate a greater variety of receivers, the M-175 transmitter
incorporates the option to operate with receivers that have companded or
non-companded audio processing. However, the M-175 transmitter must
operate non-companded with non-companded receivers and companded
only with receivers that incorporate companding processing. A mismatch
will result in unacceptable audio performance.
Basic Companding Theory
The dynamic range of the audio signal is compressed in the transmitter at a
2:1 ratio. The receiver then expands the audio signal at a complementary
1:2 ratio to restore the dynamic range of the audio signal to the original level
and also to provide additional noise reduction when no audio signal is
present.
M-175 FREQUENCY INFORMATION (Continued)