User's Manual

1
-- Crescend Technologies --
Power Amplifiers P10-xxDE1-C5-001.
Unit Description and User Manual.
1. General description.
The power amplifier (PA) is nonlinear AB to C class unit that is intended for frequency (phase) modulated
(manipulated) signals amplification.
There is the fan for forced cooling, which starts rotating, when the sufficient RF signal is applied to the unit
input, or when the heatsink inside temperature reaches +85ºC. The automatic power control loop keeps the
output power at the rated level. It reduces this level, when the load VSWR is above 2, when the heatsink
temperature exceeds +85ºC or under the outer control.
Frequency range of operation (F), MHz . . . . . . . . . . . . . . . . . . . . . . . . …138-144, 148-174;
Input power (Pin), W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see Table 1 in Block-Diagram;
Output power (Pout), W, not less than . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100;
Relative harmonic level, dBc, less than . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -70;
DC power supply voltage (Vsup), V, nominal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13.8;
Allowed DC power supply voltage tolerance, V, not greater than . . . . . . . . . . . . . . . . . +1.0;
DC current, A, not greater than . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22;
Load VSWR, not greater than . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5;
Input VSWR, less than . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7;
Operating temperature range, ºC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -30 to +60;
RF connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Ohm N (F);
DC connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 6-32 screws.
2. Schematic Description.
RF Circuitry Description.
RF signal, applied to the connector “RF IN”, proceeds via the attenuator ATT1 and the coax cable to the pad J1
of Pre-Amplifier Board. There is the attenuator ATT2 (R10…R12). The part of RF power at the output of
ATT2 comes to the input detector D1. The main of RF signal passes 10 dB attenuator (R6, R7, R8, R13) and
comes to the input of power amplifier U1.
Amplified RF signal from the pad J2 of the Pre-Amplifier Board, comes to the pad J1 of the Final Stage Board.
After 3.5 dB attenuator (RF1, R3) RF power distributes by the splitter Y1 evenly between two amplifying
modules U31 and U51.
Combined by Y2 signals go the pad J2 of the Final Stage Board, and then, to the pad J1 of the Output Board.
There is the low-pass filter (L1…L3; C12…C15), needed for the harmonics suppression, at the way of RF
signal, as well as directional couplers Y1 and Y2. These couplers together with detectors D1, D2 form DC
voltage, proportional to the forwarded and reversed RF powers at the unit output.
The unit output connector “RF OUT” is connected directly to the pad J3 of the Output Board.
Keying Circuitry Description.