Operating instructions

LOCAL OPERATION
3-71
Signal routing
The tones sub-mode can be entered from either Tx TEST, Rx TEST, Dx TEST or AF TEST
modes.
The encoded signal produced by the Service Monitor can be routed to the equipment under test in
two ways:
• As a modulated RF signal from either of the RF output connectors.
• As an AF signal from the AF GEN OUT connector.
Similarly, an encoded signal produced by the equipment under test can be routed to the Service
Monitor in two ways:
• As a modulated RF signal to either of the RF input connectors.
• As an AF signal to the AF INPUT connector.
The input and output routing settings are made from the TONES selection screen. Pressing the
[Tones In] or [Tones Out] key alternates the setting between RF and Audio. The selected settings
will be retained until reset, either manually or by recalling Service Monitor settings. Any tone
sequence or continuous tone that is running when an input or output routing setting is changed will
be stopped.
RF input attenuators
The RF input circuits of the Service Monitor are auto-ranging under most operating conditions.
When operating in some of the tones modes this can be a disadvantage as the tones decoders need
to receive the leading burst of any transmission. Therefore when ‘TONES’ mode is selected, the
auto-ranging function is disabled and the RF input sensitivity of the service monitor is set
manually.
This is done by using the [ E ] and [ F ] keys on the TONES selection screen. For correct
operation of the TONES decoders, the input signal level should not exceed the level set.
Each keypress will switch the sensitivity of the service monitor up or down by 10 dBm. If the
level of the applied signal is unknown, it can be measured using the Tx TEST mode. The Service
Monitor
RF Input Level can then be set above the measured level.
The following table shows the RF input level settings that are available for either of the RF input
connectors.
RF N in RF Antenna in Audio
398 W 56.0 dBm 1.00 W 30.0 dBm <40.0 V
39.8 W 46.0 dBm 100.0 mW 20.0 dBm <20.0 V
3.98 W 36.0 dBm 10.0 mW 10.0 dBm <10.0 V
398 mW 26.0 dBm 1.00 mW 00.0 dBm <4.0 V
39.8 mW 16.0 dBm 100
µW
-10.0 dBm <2.0 V
3.98 mW 6.0 dBm 10
µW
-20.0 dBm <1.0 V
398
µW
-4.0 dBm 1
µW
-30.0 dBm <400 mV
40
µW
-14.0 dBm -40.0 dBm <200 mV
4
µW
-24.0 dBm -50.0 dBm <100 mV
When using the AF INPUT connector for TONES operation, the [ E ] and [ F ] keys on the
TONES selection screen set the AF input sensitivity. The column headed
Audio, in the above
table, lists the AF input settings. The AF input signal level should be less than that shown for the
current setting.