To select the reference oscillator bandwidth, To restore factory default settings – Agilent Technologies E8267D PSG User Manual
Page 161
Chapter 4
147
Optimizing Performance
Adjusting Reference Oscillator Bandwidth (Option UNR/UNX/UNY)
Adjusting Reference Oscillator Bandwidth (Option UNR/UNX/UNY)
The reference oscillator bandwidth (sometimes referred to as loop bandwidth) in signal generators
with Option UNR/UNX/UNY (improved close–in phase noise <1 kHz) is adjustable in fixed steps for
either an internal or external 10 MHz frequency reference. The reference oscillator bandwidth can be
set to 25, 55, 125, 300, or 650 Hz; models without Option UNR/UNX/UNY have a fixed reference
oscillator bandwidth.
At frequency offsets below approximately 1 kHz, the stability and phase noise are determined by the
internal or external frequency reference. At frequency offsets above 1 kHz, stability and phase noise
are determined by the synthesizer hardware.
To optimize the overall phase noise performance of the signal generator for your particular
application, make this adjustment depending on your confidence in the stability and phase noise of
the external or internal reference versus the synthesizer hardware for various frequency offsets from
the carrier.
To Select the Reference Oscillator Bandwidth
When using the internal bandwidth reference:
1.
Press
Utility
>
Instrument Adjustments
>
Reference Oscillator Adjustment
>
Internal Ref Bandwidth
.
2.
Select the desired bandwidth.
When using an external bandwidth reference:
1.
Press
Utility
>
Instrument Adjustments
>
Reference Oscillator Adjustment
>
External Ref Bandwidth
.
2.
Select the desired bandwidth.
To Restore Factory Default Settings:
Internal Bandwidth: 125 Hz
External Bandwidth: 25 Hz (Option UNR), 650 Hz (Option UNX/UNY)
Press
Utility
>
Instrument Adjustments
>
Reference Oscillator Adjustment
>
Restore Factory Defaults
.
Optimizing Phase Noise and Harmonics Below 3.2 GHz (Option UNX/UNY)
Included with the Ultra- Low Phase Noise (Option UNX/UNY), is the ability to improve both phase
noise and harmonic performance below 3.2 GHz. Refer to the PSG’s Data Sheet.
This section contains the following topics:
•
“Optimizing Phase Noise Below 250 MHz (serial prefix > xx4928 and higher)” on page 148
•