2
Operation
22
Keysight 478A Operating and Service Manual
Zero Set
It is necessarily to electrically zero-set the model 431/432 power meter before
making a power measurement. To preserve the same zero reference throughout
the measurement, maintain the same thermal environment when RF power is
applied. Two recommended set-ups for 431 zero-setup are presented in
Power Turned Off for Zero-Set”
“Thermistor Mount Disconnected
on page 23. The recommended set-up for zero-set in the 432 is
RF Power Turned Off for Zero-Set
There is minimum zero drift when the zero is set with the RF system connected to
the thermistor mount and the RF power switch off or greatly attenuated by the
generator attenuator. The methods used to switch off RF output in Keysight signal
generators are listed in
. After allowing time for the mount to stabilize
thoroughly, follow zero-set procedures in the 431 or 432 power meter manual and
then turn on the RF source.
Table 2-1
Methods of Switching Off RF Output of Various Keysight Signal
Generators
Keysight Generator
Frequency Range
Procedure to Switch Off RF
Output
Model 606
50 kHz to 65 MHz
Increase the generator output
attenuation 30 or more dB
Model 8614A / 8616A
Model 614 / 616
Model 618 / 620
800 to 2400 MHz / 1800 to 4500 MHz
800 to 2100 MHz / 1800 to 4200 MHz
3.8 to 7.6 GHz / 7 to 11 GHz
Release RF push button
Set modulation selector to OFF
Set modulation selector to OFF
Model 608
Model 682 / 687
10 to 480 MHz / 10 to 420 MHz
1 to 2 GHz / 12.4 to 18.0 GHz
Set MOD SELECTOR to PULSE,
but do not apply modulation
signal to modulation input
terminal
Model 612
450 to 1230 MHz
Set MOD SELECTOR to PULSE
2, but do not apply modulation
signal to modulation input
terminal
Model 690, 8690 Series
1 to 20 GHz
Set LINE to STANDBY
Содержание 478A
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Страница 13: ...Keysight 478A Thermistor Mount Operating and Service Manual 13 1 General Information Introduction 15...
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Страница 17: ...Keysight 478A Thermistor Mount Operating and Service Manual 17 2 Operation Biasing Thermistors 18...
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Страница 33: ...Keysight 478A Thermistor Mount Operating and Service Manual 33 4 Maintenance Mechanical Shock 34...
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Страница 45: ...Keysight 478A Thermistor Mount Operating and Service Manual 45 A Appendix A Introduction 46 Manual Changes 47...