User guide

MS-DMT Guide v1.04
Released 05-30-2014
135
The radio frequency accuracy shall be within ±30Hz for manpack equipment and within ±10Hz
for all other equipment. The frequency stability of the transmitter carrier frequency shall be 1 x
10-8 per day or better (± 10Hz in 30 days).
The transmitter ALC action shall be implemented in such a way as to not degrade waveform
performance e.g. switch-off and/or set very slow in data mode.
The change-over time between transmit and receive modes shall meet the following
requirements:
(a) Transmit to receive changeover time shall not be greater than 15ms from keying-off for the
receiver to achieve 90% of full specified sensitivity.
(b) Receive to transmit changeover time shall not be greater than 25ms (10ms highly desirable)
from keying-on for the transmitter to achieve 90% of full specified output power.
The Receiver Automatic Gain Control requirements apply to receivers that employ AGC. Any
change in input level above the receiver AGC threshold shall produce an output change of less
than ±3dB.
The AGC time constants during non-data operating modes shall be as follows:
a. Attack: <30ms
b. Decay: between 500ms and 1.5sec.
The AGC time constants during single channel (not Link 11) data communications shall be as
follows:
a. Attack: <10ms