Sailor COMPACT HF SSB T2130, Техническое руководство

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2 INSTALLATION MECHANICAL HF SSB TRANSMITTER T2130
- Vforward maximum.
The predetermined maximum allowable Vforward level is composed of a number of parameters. This
composition of the maximum allowable Vforward is described in a section below. In the following it is
assumed that the maximum allowable Vforward has already been calculated.
The predetermined maximum allowable Vforward level will in the following sections be mentioned as
Vf_ max (Vforward maximum).
- RF level control.
A digitally controlled step attenuator with 64 steps, each step is approx. 0.3 dB, is placed in the Exciter
Unit (4) in the RE2100. During the automatic power setting the TX-processor (3) in the T2130 has the
full control of the step attenuator via the SP-Bus and the Processor Module (5) in the RE2100.
FUNCTIONAL DESCRIPTION OF THE AUTOMATIC POWER SETTING
When the automatic power setting is about to start the step attenuator in the Exciter Unit (4) is preset to
step 43 by the answer to the first ‘Tune’ command.
The automatic power setting may now take place in 2 or 3 states, depending on the initial measured
Vforward (step 31) related to the Vf_max.
- State 1 is always run as the first state.
- State 2 is run when the RF-level has to be increased one or several steps.
- State 3 is always run as the last state in the automatic power setting.
STATE 1
The Vforward level (step 43) is measured by the TX-processor and compared to 4 different levels:
- A minimum level.
If Vforward is lower, then an error is generated. The Vforward level is too low.
- Vf_max - 0.6 dB.
If Vforward is lower, then a number of steps is calculated for increasing the RF-level out of the Exciter.
The calculation is described below. The automatic power setting continues at state 2.
- Vf_max.
If Vforward is lower or equal to, then the step is increased with one, The automatic power setting
continues at state 2.
- 0.3 dB.
If Vforward is lower, then the automatic power setting
continues at state 3. Else an error is generated. The Vforward level is too high.
STEP CALCULATION
In order to reduce the time used for the automatic power setting the RFlevel is increased a number of steps
initially. The number of steps ‘n’ is calculated in the following way:
Vf_max = 10 ((A / 20)) * n
------------
Vforward
Where A is the resolution of the step attenuator in dB. Theoretically A should be = 0.3 dB/step. However,
there is some compression in the amplifiers, etc. involved. Iterations have shown that A = 0.43 dB/step
is suitable in order to reach the correct power level in an acceptable time without overshooting.
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