Comparing Pulsed Amplifiers to CW Amplifiers
Pulsed signals are primarily defined by
- rise and fall time
- pulse width
- duty cycle (pulse-to-pause ratio)
- pulse repetition frequency (P-RF)
- droop (power level drop during pulse width / duration)
It is critical for pulsed signals that the required current is directly available fast in time at the final stage transistors.
There are many difficult combinations of pulse width and pulse repetition frequency.
Identifying specific timing to the amp supplier in advance we will ensure that they are ideally / perfectly amplified
Pulse Elements
Pulse Timing
Pulse Modulator
Samples of Power Amplifer Pulse Responses
At 800 ps
At 2 ns
At 5 ns
At 20 ns
Solid State RF Pulsing Technology
For wideband ranges no dedicated pulsed transistors are available. Therefore, using CW transistors the optimization for pulsed operation is not that ideal. However, power supplies and cooling can be reduced accordingly. Specifically at higher output levels it remains important.
- 150 - 4000 MHz
- 1 - 10 GHz
- Narrow band amplifiers only at this time
- Typical duty cycle of pulsed power solid state designs is 10%
- Typical pulse width is 100 µs
Pulsed travelling wave tube amplifiers cover
- Cover 2 - 18 GHz with two amplifiers
- up to 30 kW pk
- Significantly higher output power levels than standard CW tubes
- Typical duty cycle of travelling wave tube designs is 1 … 6%
- Standard pulse width is 50 µs; optional for some tubes 100 µs
Did You Know?
Every CW amplifier is capable of amplifying pulsed signals?
SSP series pulsed amplifiers up to approximately 10 kW pk
Common Standards Requiring Pulse Power Testing
Automotive Radar Pulse Testing
GM GMW 3097S
1.2 … 1.4 GHz, 600 V/m at 0.75 m and 1 % Duty
Ford EMC-CS-2009.1
1.2 … 1.4 GHz and 2.7 … 3.1 GHz, 300 or 600 V/m at 1 m and 1% Duty
FCA (Fiat Chrysler) CS.0054
0.8 … 2.7 GHz, 50 V/m at 1 m and 1% Duty
VOLVO 515-0003
1.15 … 1.45 GHz, 600 V/m and 10% Duty
2.6 … 3.2 GHz, 5.2 … 5.9 GHz and 8.2 … 12.4 GHz, 200 V/m at 1 m and 10% Duty
Autonomous Driving
Preliminary
8.5 … 10.5 GHz, 600 V/m at 1 m and 50% Duty
15.7 … 17.7 GHz, 600 V/m at 1 m and 50 % Duty
Aerospace
RTCA/DO-160
Section 20.0: Radio Frequency Susceptibility (Radiated and Conducted), Category R
0.4 … 8 GHz, 150 V/m at 1 m and 4% Duty
MIL Testing
MIL 461x, RS103
2 MHz … 18 GHz, 200 V/m at 1 m and 50% Duty