Agilent Technologies E8285A manual Input Atten, Ator hold mode, Information

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

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