It is strongly prohibited to turn on the generator without the load
(with the open HV connector). We recommend using 50 centimeters
length coaxial cable between the generator and the load (antenna or
first attenuator) to prevent damage to the generator in the case of
load breakdown.
Operation on unmatched load inevitably results in reflection from the
load. Part of the pulse energy returns back to the generator and may overheat it.
PPM0732 has overheating protection. If the temperature exceeds 55 ºC, then the
red LED "OVERHEAT" lights on and the triggering is blocked. Please cool down
the generator and reduce the repetition rate if required.
Please provide free airflow around the generator during long-time
operation at high frequency, especially if the load is unmatched.
The generator is triggered by the leading edge of the external triggering
pulse. There is no internal triggering mode. Acceptable triggering pulse amplitude
is +3.5V … +5V at 50 Ohm. Low triggering pulse amplitude leads to unstable
triggering and increases output pulse jitter. The recommended triggering pulse
width is 170 ns, while the acceptable range is 10 ns ... 1000 ns. Pulse rise and fall
time should be no more than 1 ns. Longer rise/fall time may increase the output
pulse jitter. Orange LED "SYNC IN" lights on in the case of successful triggering.
There is an integrated Phase Locked Loop (PLL) circuit that controls the
output pulse position in time and synchronizes it with the trailing edge of the
triggering pulse, if the triggering pulse width stays within 168 ns …175 ns.
Fig.3. PPM0732 block diagram.
The block diagram of PPM0732 is shown in Fig.3. It consists of the
control system, DSRD/SAS output stage, power MOSFETs, drivers, as well as the
phase detector and variable delay circuit.
PPM0732 User Manual 5
