Operating instructions

LOCAL OPERATION
3-64 46882-311D
adjusted by use of the variable control (or the data entry keys) to 1,495 Hz, the next incremental
step down will produce a frequency of
995 Hz.
The assignment and value of a incremental setting will be retained, with the mode setup, when a
different mode is selected or the instrument is powered down. This is of particular note when
assigned to the AF generators as they are also the modulation generators within the Rx TEST
mode and the AF generators within the AF TEST mode.
The incremental keys cannot be used when in the Dx TEST mode.
Use within spectrum analyzer mode
The SPEC ANA mode makes use of the FREQ [ ] and [ ] keys for span adjustment. The span
is ranged up or down in a 1, 2, 5 sequence, from 1.0 kHz to 1.0 GHz.
Adjustment to the span by these keys is linear about the centre frequency and will not adjust
below zero or above the top frequency limit.
When the
legend is highlighted the FREQ [ ] and FREQ [ ] keys will increment the
centre frequency by the value last set up in the TxTEST mode.
The LEVEL [
] and [ ] keys adjust the reference level of the spectrum analyzer in either 2 dB
or 10 dB steps depending on the setting of the reference level vertical range.
Tones
Tones sub-mode
Audio tones and digital code signals are used for many purposes within radio communication
systems. The Service Monitor has a TONES mode accessed from the Tx TEST, Rx TEST, Dx
TEST and AF TEST modes.
This gives facilities for testing tone calling and control systems of the following types.
• Sequential Tones. A selective calling system using audio tones.
• CTCSS (Continuous Tone Coded Squelch System).
• DCS (Digitally Coded Squelch).
• DTMF (Dual Tone, Multi-Frequency).
• POCSAG (Post Office Code Standardisation Advisory Group). A paging system
using digital signalling.
The tone mode is entered from the top level screen of any main mode, other than SYSTEM or
SPEC ANA.
Pressing the [Tones] key will display the screen shown in Fig. 3-18, Tones selection screen and
Tones mode receiver input level setting .
Fig. 3-18 Tones selection screen and Tones mode receiver input level setting