Operating instructions

LOCAL OPERATION
3-41
When testing the receiver section of a transceiver, ensure that the power output of the transmitter
section will not exceed the power handling capability of the connector on the Service Monitor.
Also ensure that the transceiver cannot be switched to ‘
TRANSMIT’ inadvertently.
The receiver and the Service Monitor should be connected as shown in Fig. 3-11 Receiver test
connections. The block diagram of the Service Monitor shows the signal routing within it.
Points to note are:-
The power source for the receiver should be reliable and stable. The battery of a vehicle
may discharge if supplying a mobile transceiver during prolonged testing or the earth
connection may become open circuit if the transceiver is removed from its normal
location.
When testing the receiver section of transceivers take precautions to prevent the
inadvertent ‘keying’ of the transmitter.
The RF input connection to the receiver should be made using good quality RF cable with
correctly fitted connectors. Worn connectors and damaged or kinked cable can produce
reflections and losses in the system which will give misleading results.
Setting up
When all the required connections have been made, select the Rx TEST mode to display the screen
shown in fold out diagram (3-0).
Set the parameters or options to suit the test requirements, from the
RECEIVER TEST menus.
Rx frequency
Range 400 kHz to 1.05 GHz
Press the [RF Gen] key.
The
GEN FREQ legend is highlighted as shown in fold out diagram (3-1).
If the Rx=Tx function has been set from the Tx TEST mode, the
GEN FREQ will be set to the
receiver frequency relevant to that test. If this is correct for the receiver under test, there is no
need to re-enter the frequency.
Manual frequency setting
With
GEN FREQ legend highlighted, data may be entered from the keyboard to the GEN FREQ
parameter. Enter the required frequency by using the digit keys and the decimal point key if
relevant. The resolution of the RF generator frequency entry is 1 Hz, but it is not necessary to
enter every digit down to the least significant place.
The entry is completed by pressing a terminator key. Using the [MHz], [kHz] or [Hz] key causes
the entered frequency to be displayed according to normal convention. The following examples
explain further.
Pressing:-
[1] [2] [5] [MHz] will display 125.000000 MHz
[1] [2] [5] [kHz] ” “ 125.000 kHz
[1] [2] [5] [0] [kHz] ” “ 1.250000 MHz
[1] [.] [2] [5] [MHz] ” “ 1.250000 MHz
[1] [2] [5] [0] [0] [0] [1] [Hz] ” “ 1.250001 MHz
Variable control
With the
GEN FREQ legend highlighted, the GEN FREQ parameter can be adjusted by using the
variable control.
Frequency increment
The FREQ [×] and [ Ø] keys can be assigned to RF generator frequency adjustment. See
Incremental adjustments which starts on page 3-68.