Product specifications

Device Types

Figure 1 shows two types of pulse operation modes, pulsed-RF and pulsed-

bias. Pulsed-RF operation drives the device with a pulse-modulated RF

signal while the DC bias is always on. Amplifiers in receivers used in pulse-

modulated applications are typically tested under pulsed-RF operation. Testing

devices in pulsed-RF operation requires RF pulse modulators for the stimulus

as well as pulse generators to drive the RF modulator and to synchronize or

gate the VNA receivers to capture the modulated RF signals. The pulsed-bias

operation is when the DC bias is switched on and off to generate a pulse-

modulated signal while the input is mostly a CW signal and is always on.

Traveling-wave-tube (TWT) amplifiers are one example of this type and are

commonly used in radar transmitters. The RF pulse modulator is not required

for the stimulus in this mode, but pulse generators are needed to turn on and

off the DC bias and synchronize the VNA receivers to measure the output

signal when the device is on.

Figure 1. Pulsed-RF and pulsed-bias operation modes

Pulsed-RF Pulsed-bias

Input: pulsed

Output: pulsed

DC bias: always on

Input: CW

Output: pulsed

DC bias: pulsed