A07A2200S
4.6.10 By entering PAGE UP the following screen shot is accessed :
In this screen shot the output frequency can be set by the usual cursors with a resolution of 10KHz.
On the display the current frequency and the new value appear.
After the ENTER key has been pressed for the new value, the output power is disabled for a few
seconds, allowing the oscillator to exactly reach the new value.
4.6.11 By entering PAGE UP, the following screen shot is accessed:
127
All the rules concerning the radio transmitters in FM band include some limits of accuracy and
stability of the output frequency. These limits usually depend on parameters of internal crystal
reference, which are at the same time connected firstly to the temperature and ageing of the crystal
itself. For this reason the crystal is heated at a constant temperature of 55°C, which guarantees a
considerable thermal stability, however a frequency correction due to ageing is easily implemented
just manually.
The present screen shot allows a very fine adjustment of the frequency value assigned to the radio
station without the need to open the transmitter. By entering a correction factor between 0 and 255,
the transmitter frequency can be corrected with a 20Hz step only; this operation can be performed
during the normal periodical check of the transmitter or, as it is shown below, through a remote
telecontrol.
By entering the new correction value, it’s possible to reach a 2KHz offset in comparison to the
central value.
380 221 R02 Pag. 21
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