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WCDMA3G_ErrorVector


Description: EVM error vector
Library: 3GPPFDD 10-99, Measurement
Class: SDFWCDMA3G_ErrorVector

Parameters

Name Description Default Type Range
StartSym start symbol 2560 int [0, 10000]
SymBurstLen number of symbols within burst to be measured 2560 int [1, 10000]
SampPerSym number of samples per symbol 16 int [1, 512]
SymDelayBound upper bound of delay detection, in symbol, -1 for no detection -1 int [-1, 1000] †
NumBursts number of bursts to be measured 1 int [1, ∞)
FilterLength Number of taps 64 int [2, 128]
† -1 means no synchronization is needed

Pin Inputs

Pin

Name

Description

Signal Type

1

in

signals to be measured for EVM

complex

2

ref

reference signals for EVM measurement

complex

Notes/Equations
  1. This subnetwork is used to calculate EVM error vector according to the tested and reference signals. The following figure shows the schematic of this subnetwork.

    WCDMA3G_ErrorVector Schematic
  2. Each firing, one input token is consumed at each input pin while one output token is produced at the output token. The data sequence size that represents the valid error vector is SymBurstLen × NumBursts. The error vector is measured at each symbol instead of each sample.
    Results are split into Real and Imag parts and saved in the Realerror.txt and Imagerror.txt files, respectively.
  3. The error vector is obtained by calculating the EVM. Let Z(k) be the complex vectors produced by observing the real transmitter through a specified measuring receiver filter at instant K, one symbol period apart. S(k) is defined to be an ideal transmitted signal observed through the measuring filter and sampled at time k. With the transmitter modeled as:

    where

    W = edr + jda accounts for both a frequency offset giving da radians per symbol phase rotation and an Amplitude change of dr nepers per symbol;
    C0 is a constant origin offset representing quadrature modulator imbalance;
    C1 is a complex constant representing the arbitrary phase and output power of the transmitter;
    E(k) is the residual vector error on sample S(k).

    The error vector E(k)

    is measured and calculated for each instant k.
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