Agilent Technologies N9010A specifications 124

W-CDMA Measurement Application

Amplitude

b.The Fast method has a slight decrease in accuracy in only one case: for BTS measurements at 5 MHz offset, the accuracy degrades by ±0.01 dB relative to the accuracy shown in this table.

c.To meet this specified accuracy when measuring mobile station (MS) or user equipment (UE) within

3 dB of the required −33 dBc ACPR, the mixer level (ML) must be optimized for accuracy. This opti- mum mixer level is −22 dBm, so the input attenuation must be set as close as possible to the average input power − (−22 dBm). For example, if the average input power is −6 dBm, set the attenuation to

16 dB. This specification applies for the normal 3.5 dB peak-to-average ratio of a single code. Note that if the mixer level is set to optimize dynamic range instead of accuracy, accuracy errors are nominally doubled.

d.ACPR accuracy at 10 MHz offset is warranted when the input attenuator is set to give an average mixer level of −14 dBm.

e.In order to meet this specified accuracy, the mixer level must be optimized for accuracy when measur- ing node B Base Transmission Station (BTS) within 3 dB of the required −45 dBc ACPR. This opti- mum mixer level is −19 dBm, so the input attenuation must be set as close as possible to the average input power −(−19 dBm). For example, if the average input power is −5 dBm, set the attenuation to

14 dB. This specification applies for the normal 10 dB peak-to-average ratio (at 0.01% probability) for Test Model 1. Note that, if the mixer level is set to optimize dynamic range instead of accuracy, accu- racy errors are nominally doubled.

f.Agilent measures 100% of the signal analyzers for dynamic range in the factory production process. This measurement requires a near-ideal signal, which is impractical for field and customer use. Because field verification is impractical, Agilent only gives a typical result. More than 80% of prototype instru- ments met this “typical” specification; the factory test line limit is set commensurate with an on-going 80% yield to this typical.

The ACPR dynamic range is verified only at 2 GHz, where Agilent has the near-perfect signal avail- able. The dynamic range is specified for the optimum mixer drive level, which is different in different instruments and different conditions. The test signal is a 1 DPCH signal.

The ACPR dynamic range is the observed range. This typical specification includes no measurement uncertainty.

g.3GPP requires the use of a root-raised-cosine filter in evaluating the ACLR of a device. The accuracy of the passband shape of the filter is not specified in standards, nor is any method of evaluating that accuracy. This footnote discusses the performance of the filter in this instrument. The effect of the RRC filter and the effect of the RBW used in the measurement interact. The analyzer compensates the shape of the RRC filter to accommodate the RBW filter. The effectiveness of this compensation is summa- rized in three ways:

−White noise in Adj Ch: The compensated RRC filter nominally has no errors if the adjacent channel has a spectrum that is flat across its width.

−TOI-induced spectrum: If the spectrum is due to third-order intermodulation, it has a distinctive shape. The computed errors of the compensated filter are −0.004 dB for the 470 kHz RBW used for UE testing with the IBW method and also used for all testing with the Fast method, and 0.000 dB for the 30 kHz RBW filter used for BTS testing with the IBW method. The worst error for RBWs between these extremes is 0.05 dB for a 330 kHz RBW filter.

−rms CW error: This error is a measure of the error in measuring a CW-like spurious component. It is evaluated by computing the root of the mean of the square of the power error across all frequencies

within the adjacent channel. The computed rms error of the compensated filter is 0.023 dB for the 470 kHz RBW used for UE testing with the IBW method and also used for all testing with the Fast method, and 0.000 dB for the 30 kHz RBW filter used for BTS testing. The worst error for RBWs between these extremes is 0.057 dB for a 430 kHz RBW filter.

124 Chapter 9