ITC 220 Base Station, Locomotive & Wayside Radio Transceiver Field Service Guide PN 0046300120 Rev. A
| Page 40
STOP
SCHED,DEL,ALL
DSP_MODE,IDLE
DSP_MODE,TEST
L1_TEST,SET,TXFREQ,value
L1_TEST,SET,TXMOD,DQPSK
L1_TXDUTY,1000,300,0
where:
value
equals the desired frequency of operation in Hz.
Note:
The ratio of 300/1000 denotes a 30% transmit duty cycle.
2.
Once observation of radio performance is complete, turn off transmit operations by typing:
L1_TEST,STOP
To key up a Base Station or Locomotive transmitter at π/4DQPST half rate:
(Base Station or Locomotive only)
1.
In
XtermW
type the following commands:
STOP
SCHED,DEL,ALL
DSP_MODE,IDLE
DSP_MODE,TEST
L1_TEST,SET,TXFREQ,value
L1_TEST,SET,TXMOD,DQPSK_HALF
L1_TXDUTY,1000,300,0
where:
value
equals the desired frequency of operation in Hz.
Note:
The ratio of 300/1000, specified for Base Station and Locomotive Transceivers, denotes a 30% transmit
duty cycle. (The maximum transmit duty cycle for Wayside Transceivers must be held to less than 10%. The
ratio of 300/3500, you will see specified for the Wayside Transceiver in the next section, denotes
approximately a 9% transmit duty cycle.)
2.
Once observation of radio performance is complete, turn off transmit operations by typing:
L1_TEST,STOP
Note
— The two following figures in this section show a typical transmission spectrum or power measurement of a
Locomotive Transceiver at Full DQPSK.