The Very Old Glossary of Black-Box Digital Signal Processing Virtual Blocks

4-Bit A/D Converter Block

This is a 5-pin mixed-signal device with an analog input and 4 digital outputs. Based on the specified maximum input voltage level, a total of 16 discrete voltage levels are established. The block fits the input analog voltage between two of these 16 discrete levels and outputs the 4-bit binary equivalent to 4 digital pins B0-B3 representing the LSB and MSB, respectively.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
max_val	maximum input voltage	V	5

4-Bit D/A Converter Block

This is a 5-pin mixed-signal device with 4 digital inputs and an analog output. Based on the specified low and high output voltage levels, a total of 16 discrete voltage levels are established. The block converts the input 4-bit word (B0-B3 representing the LSB and MSB, respectively) to the corresponding discrete voltage level and outputs it as an analog voltage signal.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
out_low	output low voltage level	V	0
out_high	output high voltage level	V	5

4-Bit Signal Digitizer Block

This is a 6-pin mixed-signal device with an analog input, a digital clock and 4 digital outputs. It samples its analog input signal at the period of the supplied digital clock. The digitized version of the input signal is sent out to 4 digital outputs B0-B3 representing the LSB and MSB, respectively.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
r_in	input resistance	Ω	10G
max_val	maximum input voltage	V	5

8-Bit A/D Converter Block

This is a 9-pin mixed-signal device with an analog input and 8 digital outputs. Based on the specified maximum input voltage level, a total of 256 discrete voltage levels are established. The block fits the input analog voltage between two of these 256 discrete levels and outputs the 8-bit binary equivalent to 8 digital pins B0-B7 representing the LSB and MSB, respectively.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
max_val	maximum input voltage	V	5

8-Bit D/A Converter Block

This is a 9-pin mixed-signal device with 8 digital inputs and an analog output. Based on the specified low and high output voltage levels, a total of 256 discrete voltage levels are established. The block converts the input 8-bit word (B0-B7 representing the LSB and MSB, respectively) to the corresponding discrete voltage level and outputs it as an analog voltage signal.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
out_low	output low voltage level	V	0
out_high	output high voltage level	V	5

Clocked Sample-and-Hold Block

This device samples its input signal at a specified sampling period and holds the values of each sample during each clock cycle. The output signal is a quantized version of the input signal.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
duty_cycle	sampling pulse duty cycle	-	0.1
Tmax	signal period or maximum duration	sec	10

Digital Integrator Block

This device models a digital integrator with a Z-transform of -z^-1/2, which is equivalent to a delay line with a delay of half the sampling period

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required

Discrete Convolution Block

These blocks perform an N-point discrete convolution of their input signals. Both of the input signals x(t) and h(t) are sampled at the specified sampling period. The samples of x(t) are then shifted in time for the convolution. The output signal is a pulse train of the same period with the specified duty cycle. The input signal of these block can be either continuous-time signals or pulse trains of the specified period.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
rise_time	window rise time	sec	0
fall_time	window fall time	sec	0
duty_cycle	output pulse duty cycle	-	0.1
gain	output gain	-	1

Discrete Fourier Transform (DFT) Block

These blocks perform an M-point discrete Fourier transform (DFT) of their input signal and then sample each period of the Fourier transform N times in the frequency domain. The output signals are two finite sequence pulse trains representing the cosine and sine DFT transforms. The input signal of these block can be either a continuous-time signal or a pulse train of the specified period.

There are ten DFT blocks for M = 5, 6, 7, 8, 9, 10, 12, 16, 32, 64. In each case, the total duration of the transform window is MT, where T is the sampling period. By default, the frequency domain sampling starts at t = MT and takes place over one spectral period equal to f_s = 1/T. You can change the sampling start time by "n_delay" temporal periods. n_delay = 0 by default, but it can be either positive or negative. You can also extend spectral sampling to more than one spectral period by increasing the value of the parameter "n_dur", which has a default value of 1.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
N	sequence length	-	5	required
rise_time	window rise time	sec	0
fall_time	window fall time	sec	0
duty_cycle	output pulse duty cycle	-	0.1
n_delay	number of delayed period before sampling	-	0
n_dur	number of frequency-sampled periods	-	1

Discrete-Time Fourier Transform (DTFT) Block

These blocks perform an N-point discrete-time Fourier transform (DTFT) of their input signal and output the transform as two temporal voltage signals representing the cosine and sine DTFT transforms. The The input signal of these block can be either a continuous-time signal or a pulse train of the specified period.

There are ten DTFT blocks for N = 5, 6, 7, 8, 9, 10, 12, 16, 32, 64. In each case, the total duration of the transform window is NT, where T is the sampling period.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
rise_time	window rise time	sec	0
fall_time	window fall time	sec	0

Discrete-Time Signal Hold Block

This device takes a pulse train of a specified period as its input and holds the value of each pulse's amplitude during each clock cycle at the output.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
duty_cycle	sampling pulse duty cycle	-	0.1
rise_time	window rise time	sec	0
fall_time	window fall time	sec	0
Tmax	signal period or maximum duration	sec	10

Finite Sequence Signal Sampler Block

This device samples its input signal during a finite time window at a specified sampling period and outputs a pulse train of finite duration with a specified duty cycle.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
duty_cycle	sampling pulse duty cycle	-	0.01
rise_time	window rise time	sec	0
fall_time	window fall time	sec	0
n	number of samples	-	5
start	start time	sec	0

Generalized Digital Filter Block

This block models a generalized digital filter characterized by a rational transfer functions in the Z-transform domain variable z:

[math] H(z) = \frac{N(z)}{D(z)} = \frac{ \sum_{m=0}^{M} b_m z^m }{ \sum_{n=0}^{N} a_n z^n } [/math]

subject to the requirement N ≥ M. To access the parameters of this block, you have to click the Edit Model... button of its property dialog.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
deg	highest degree of z in transfer function	-	2	required
coeff_den	denominator coefficients array: coefficients of powers of (-z1/2), highest power first	-	1 0 1 0 1	required
coeff_num	numerator coefficients array: coefficients of powers of (-z1/2), highest power first	-	1 0 0 0 0	required
freq	sampling frequency	Hz	1	required

One-Shot Sample-and-Hold Block

This device follows its input signal and samples it at a specified instant of time. It holds the value of that sample at its output indefinitely.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
Tmax	signal period or maximum duration	sec	10

Signal Sampler Block

This device samples its input signal at a specified sampling period and outputs a pulse train with a specified duty cycle.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T	sampling period	sec	1	required
duty_cycle	sampling pulse duty cycle	-	0.01
rise_time	window rise time	sec	0
fall_time	window fall time	sec	0

Temporal Window Block

This device gates its input signals in time from instant t = T1 to instant t = T2.

Parameters:

NAME	PARAMETER	UNITS	DEFAULT	NOTES
T1	start time	sec	0
T2	stop time	sec	1m
rise_time	window rise time	sec	0
fall_time	window fall time	sec	0

 

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