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3 VMA Mode

3.1 Digital Demod Measurement

Using the Electronic Attenuator: Pros and Cons

The electronic attenuator offers finer steps than the mechanical attenuator, has no

acoustical noise, is faster, and is less subject to wear.

The “finer steps” advantage of the electronic attenuator is beneficial in optimizing

the alignment of the instrument dynamic range to the signal power in the front

panel as well as remote use. Thus, you can achieve improved relative signal

measurement accuracy. Compared to a mechanical attenuator with 2dB steps, the

1dB resolution of the electronic attenuator only gives better resolution when the

odd-decibel steps are used. Those odd-decibel steps are less accurately calibrated

than the even-decibel steps, so one tradeoff for this superior relative accuracy is

reduced absolute amplitude accuracy.

Another disadvantage of the electronic attenuator is that the spectrum analyzer

loses its “Auto” setting, making operation less convenient.

Also, the relationship between the dynamic range specifications (TOI, SHI,

compression, and noise) and instrument performance are less well-known with the

electrical attenuator. With the mechanical attenuator, TOI, SHI, and compression

threshold levels increase dB-for-dB with increasing attenuation, and the noise floor

does as well. With the electronic attenuator, there is an excess attenuation of about

1 to 3dB between 0 and 3.6GHz, making the effective TOI, SHI, and so forth, less

well known. Excess attenuation is the actual attenuation relative to stated

attenuation. Excess attenuation is accounted for in the instrument calibration.

Adjust Atten for Min Clipping

Sets the combination of mechanical and electronic attenuation and gain based on

the current measured signal level so that clipping will be at a minimum.

This is an immediate action function, that is, it executes once, when the control is

pressed.

The algorithms that are used for the adjustment are documented under "Pre-Adjust

for Min Clipping" on page 1773.

Remote Command

[:SENSe]:POWer[:RF]:RANGe:OPTimize IMMediate

Example

:POW:RANG:OPT IMM

Notes Executing Adjust Atten for Min Clipping initiates the measurement

Dependencies Does not appear in the Swept SA, RTSA, Monitor Spectrum and Complex Spectrum measurements

Appears in the Waveform measurement in BASIC and 5G NR Modes

Adjust Atten

Allows you to select;

Vector Modulation Analyzer Mode User's &Programmer's Reference 240

Keysight x-series Programmer's Reference

Other manuals for Keysight x-series