Agilent Technologies N9010A specifications 104

I/Q Analyzer

Frequency

Description	Specifications	Supplemental Information
Clipping-to-Noise Dynamic Rangea		Excluding residuals and spurious
		responses
Clipping Level at Mixer		Center frequency ≥ 20 MHz
IF Gain = Low	−10 dBm	−8 dBm (nominal)
IF Gain = High	−20 dBm	−17.5 dBm (nominal)
Noise Density at Mixer	(DANLc + IFGainEffectd) +	Example f
at center frequencyb	2.25 dBe

a.This specification is defined to be the ratio of the clipping level (also known as “ADC Over Range”) to the noise density. In decibel units, it can be defined as clipping_level [dBm] − noise_density [dBm/Hz]; the result has units of dBfs/Hz (fs is “full scale”).

b.The noise density depends on the input frequency. It is lowest for a broad range of input frequencies near the center frequency, and these specifications apply there. The noise density can increase toward the edges of the span. The effect is nominally well under 1 dB.

c.The primary determining element in the noise density is the “Displayed Average Noise Level” on page 44.

d.DANL is specified with the IF Gain set to High, which is the best case for DANL but not for Clip- ping-to-noise dynamic range. The core specifications “Displayed Average Noise Level” on page 44, gives a line entry on the excess noise added by using IF Gain = Low, and a footnote explaining how to combine the IF Gain noise with the DANL.

e.DANL is specified for log averaging, not power averaging, and thus is 2.51 dB lower than the true noise density. It is also specified in the narrowest RBW, 1 Hz, which has a noise bandwidth slightly wider than 1 Hz. These two effects together add up to 2.25 dB.

f.As an example computation, consider this: For the case where DANL = −151 dBm in 1 Hz, IF Gain is set to low, and the “Additional DANL” is −160 dBm, the total noise density computes to

−148.2 dBm/Hz and the Clipping-to-noise ratio for a −10 dBm clipping level is −138.2 dBfs/Hz.

104 Chapter 6