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S:\agilent\e8285\REFGUIDE\MANUAL\fields.chp
Chapter 4, Description of Fields
Fields
Input Atten
Input Attenuation sets the amount of input attenuation for the RF IN/OUT and
ANTENNA IN connectors. This function controls two settings:
• The upper field determines if you want the instrument to set the attenuation automati-
cally (Auto), or if you want to set the value manually (Hold).
• The lower field displays the present attenuation value, and is used to set the desired at-
tenuation level when the upper area is set to Hold.
NOTE: Oscilloscope and Decoder Interference. After a signal is input, the RF autoranging function
(Auto) takes a small amount of time to determine the required input attenuator setting. If your
transmitter begins sending encoded information the instant it transmits, the initial encoded
information may not be decoded during the autoranging process. The same situation can arise
when trying to display the first part of the demodulated signal on the Oscilloscope.
NOTE: When decoding a signaling sequence using the decoder, or when trying to capture the initial
modulation waveform of a signal on the Oscilloscope, set the upper field to Hold and set the
lower field to an appropriate level for the signal being decoded (start with 40 dB).
GPIB Example
“DISP CSP;CSP:ATT:MODE ‘HOLD’”
displays the CDMA REVERSE CHANNEL SPECTRUM screen and selects attenu-
ator hold mode.
Operating Considerations
Input Attenuator autoranging can interfere with oscilloscope or signaling decoder
operation under certain conditions.
See "Input Atten" on page 276 for additional
information.
Maximum signal levels at each port are printed on the front panel.
This field is displayed on the spectrum analyzer when the
Controls field is set to
Auxiliary.
Setting the upper field to
Hold prevents the RF autoranging process from
interrupting Spectrum Analyzer operation when a signal is first measured. This
can be helpful when you need to see the signal the instant the source is input, but
requires you to set the needed amount of input attenuation.
Range of Values for Hold
•0 dB
• 20 dB
• 40 dB