Estimator Category Block Listing

The following blocks are included in the Estimator category :

• Average Power
• BER Control (# Errors)
• BER Curve Control
• Bit/Symbol Error Rate
• Correlation
• Delay Estimator
• Event Time
• File Correlation
• Frequency Counter
• Mean
• Median
• MinMax
• Variance
• Vector Correlation
• Weighted Mean

Average Power

Two versions of this block exist: one for complex signals and one for real signals. These blocks estimate the average power of the input signal. Two power estimation modes are available: running and sliding window. The average power reading can be reset during the simulation (running mode only).

BER Control (# Errors)

This block is used to automatically control the generation of BER curves. It allows the user to specify a desired number of errors to observe for up to ten consecutive iterations of the simulation.

This block operates in conjunction with a plot block configured in XY mode to plot the resulting BER curve. At the end of the last run, an optional written BER summary message is also provided.

BER Curve Control

This block is used to automatically control the generation of BER curves. It allows the user to specify individual run times (in seconds) for up to ten consecutive iterations of the simulation.

This block operates in conjunction with a plot block configured in XY mode to plot the resulting BER curve. At the end of the last run, an optional written BER summary message is also provided.

Bit/Symbol Error Rate

This block compares a recovered data stream to a reference data stream and can compute either a Bit Error Rate (BER) or a Symbol Error Rate (SER).

Correlation

Two versions of this blocks are provided, one Real and the other Complex. These blocks perform a Real or Complex sliding correlation between the input signal and a reference signal. The correlation is performed over a variable window size. Two modes are available: standard and gated control.

In standard correlation mode, the two signals are continuously shifted through the correlation window. In gated control mode, the input signal is still continuously shifted through the window, but the reference signal is only shifted when the external gate signal is low. This latter mode can be used to implement a matched filter or convolution against a fixed waveform by “sliding in” the desired waveform and then locking the control gate.

Delay Estimator

This block estimates the propagation time delay between two signals in a simulation. The delay is estimated by performing a sliding correlation between a delayed signal and an undelayed reference signal. The output signal can be a distorted version of the input signal. The size of the correlation window is specified as a parameter. An output flag is provided that indicates when the entire delay range was successfully searched.

Event Time

This block provides the simulation time at which the input signal first meets a logical condition relative to a threshold parameter. Available choices include: =, >=, <=, >, and <.

File Correlation

Two versions of this blocks are provided, one Real and the other Complex. These blocks perform a Real or Complex sliding correlation between the input signal and a fixed local signal specified via an external file. The correlation is performed over a sliding window of size N, where N is a user-defined parameter. The external file provides the local tap values for the correlator. The tap values from the file can be loaded either forwards or backwards.

For efficiency purposes, an external enable input is used to control when the correlation calculation is performed. An input clock signal is required to read the input signal.

Frequency Counter

This block implements a digital frequency counter. The block operates by counting the number of high-to-low and low-to-high signal transitions within a specified time interval. Block parameters include the high and low signal thresholds and the measurement interval if appropriate. The measurement interval can be either specified as a fixed time span, or controlled externally via an enable input.

At the completion of each measurement interval, a new frequency estimate is generated and the result update clock is pulsed high (unity impulse). This block can be triggered repeatedly to provide continuous frequency estimates.

Mean

This block estimates the mean of the input signal. Two modes are available: running and sliding window. The output reading can be reset during the simulation (running mode only).

Median

This block computes the moving median of the input signal. The median is defined as the value where half the data points are larger and half are smaller. The block operates by sorting the input data points in ascending order and returning the value closest to the middle (odd N case). When the size N of the sliding window is even, the returned value is the average of the two center data points.

MinMax

This block outputs the minimum and maximum values of the input signal since the beginning of the simulation or the last reset event. An external input is provided to reset the min and max values during the course of a simulation.

Variance

This block estimates the mean and variance of the input signal. Two modes are available: running and sliding window. The output readings can be reset during the simulation (running mode only).

Vector Correlation

This block performs a real valued sliding correlation between the input signal and an external data vector. The correlation is performed over a sliding window of size N, where N represents the size of the external vector and is a user-defined parameter.

For efficiency purposes, an external enable input is used to control when the correlation calculation is performed. The calculation is performed only when the enable input is high (>= 1). An input clock signal must be provided for the input signal.

Weighted Mean

This block computes the weighted mean of the input signal by including into the mean calculation an externally provided weight value. Two modes are available: running and sliding window. The output reading can be reset during the simulation (running mode only).