Solar Electronics 9354-2 - 10. SWR & Discharge Voltage

Solar Electronics Company
10. SWR & Discharge voltage:
The Model 9354-2 Displayed discharge voltage is in reference to the open circuit discharge
voltage. This will coincide with an open circuit voltage onto a SOLAR 9454-1 Attenuator, 600
ohm input to 50 ohm output, with a calibrated attenuation of 40 dB.
The output impedance of the generator at each port is dependent on the waveform and/or
frequency of the transient selected. Since the 600 ohm network representing an open circuit does
not match the output impedance of the generator and the standing wave ratio (SWR) is higher; It
is important to keep the unmatched portion of the output circuit as short as possible (less than six inches),
especially at the higher frequencies.
If an attempt is made to measure the open circuit voltage and waveform above 1 MHz with an
unmatched 50 ohm cable, which is longer than 12 inches at 100 MHz (1/10 wavelength), into a
high impedance (1 megohm) spectrum analyzer, the SWR will distort the output waveform and
cause the measured output voltage and waveform to be significantly different than that of the
actual waveform.