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Comm Filters
The Windowed Integrator block creates cumulative sums of the input signal values over a sliding time window of fixed length. If the Integration period parameter is N and the input samples are denoted by x(1), x(2), x(3),..., then the nth output sample is the sum of the x(k) values for k between n-N+1 and n. In cases where n-N+1 is less than 1, the block uses an initial condition of 0 to represent those samples.
The input can be either a scalar or a frame-based matrix. If the input is frame-based, then the block processes each column independently. The output has the same sample time and matrix size as the input. double, single, and fixed-point data types are supported.
The length of the interval of integration, measured in samples.
Select the rounding mode for fixed-point operations. The filter coefficients do not obey this parameter; they always round to Nearest.
Select the overflow mode for fixed-point operations. The filter coefficients do not obey this parameter; they are always saturated.
Choose how you specify the word length and the fraction length of the filter coefficients (numerator and/or denominator). See Filter Structure Diagrams in Signal Processing Blockset™ Reference Guide for illustrations depicting the use of the coefficient data types in this block:
When you select Same word length as input, the word length of the filter coefficients match that of the input to the block. In this mode, the fraction length of the coefficients is automatically set to the binary-point only scaling that provides you with the best precision possible given the value and word length of the coefficients.
When you select Specify word length, you are able to enter the word length of the coefficients, in bits. In this mode, the fraction length of the coefficients is automatically set to the binary-point only scaling that provides you with the best precision possible given the value and word length of the coefficients.
When you select Binary point scaling, you are able to enter the word length and the fraction length of the coefficients, in bits. If applicable, you are able to enter separate fraction lengths for the numerator and denominator coefficients.
When you select Slope and bias scaling, you are able to enter the word length, in bits, and the slope of the coefficients. If applicable, you are able to enter separate slopes for the numerator and denominator coefficients. This block requires power-of-two slope and a bias of zero.
The filter coefficients do not obey the Rounding mode and the Overflow mode parameters; they are always saturated and rounded to Nearest.
Use this parameter to specify how you would like to designate the product output word and fraction lengths. See Filter Structure Diagrams and Multiplication Data Types in Signal Processing Blockset Reference Guide for illustrations depicting the use of the product output data type in this block:
When you select Same as input, these characteristics match those of the input to the block.
When you select Binary point scaling, you are able to enter the word length and the fraction length of the product output, in bits.
When you select Slope and bias scaling, you are able to enter the word length, in bits, and the slope of the product output. This block requires power-of-two slope and a bias of zero.
Use this parameter to specify how you would like to designate the accumulator word and fraction lengths. See Filter Structure Diagrams and Multiplication Data Types for illustrations depicting the use of the accumulator data type in this block:
When you select Same as input, these characteristics match those of the input to the block.
When you select Same as product output, these characteristics match those of the product output.
When you select Binary point scaling, you are able to enter the word length and the fraction length of the accumulator, in bits.
When you select Slope and bias scaling, you are able to enter the word length, in bits, and the slope of the accumulator. This block requires power-of-two slope and a bias of zero.
Choose how you specify the output word length and fraction length:
When you select Same as input, these characteristics match those of the input to the block.
When you select Same as accumulator, these characteristics match those of the accumulator.
When you select Binary point scaling, you are able to enter the word length and the fraction length of the output, in bits.
When you select Slope and bias scaling, you are able to enter the word length, in bits, and the slope of the output. This block requires power-of-two slope and a bias of zero.
Select this parameter to prevent any fixed-point scaling you specify in this block mask from being overridden by the autoscaling tool in the Fixed-Point Tool.
If Integration period is 3 and the input signal is a ramp (1, 2, 3, 4,...), then some of the sums that form the output of this block are as follows:
0+0+1 = 1
0+1+2 = 3
1+2+3 = 6
2+3+4 = 9
3+4+5 = 12
4+5+6 = 15
etc.
The zeros in the first few sums represent initial conditions. If the input signal is a sample-based scalar, then the values 1, 3, 6,... are successive values of the scalar output signal. If the input signal is a frame-based column vector, then the values 1, 3, 6,... are organized into output frames that have the same vector length as the input frames.
Integrate and Dump, Discrete-Time Integrator (Simulink® documentation)
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