serdes.VGA

Models a variable gain amplifier

Description

The serdes.VGA system object scales the amplitude of the input waveform based on a gain specified by the user.

To scale the input signal:

1. Create the serdes.VGA object and set its properties.

2. Call the object with arguments, as if it were a function.

To learn more about how System objects work, see What Are System Objects?.

Creation

Syntax

vga = serdes.VGA

vga = serdes.VGA(Name,Value)

Description

vga = serdes.VGA returns a VGA object that modifies a input waveform according to the gain defined by the user.

vga = serdes.VGA(Name,Value) sets properties using one or more name-value pairs. Enclose each property name in quotes. Unspecified properties have default values.

Example: vga = serdes.VGA('Gain',5) returns a VGA object with a multiplicative gain of 5.

Properties

Unless otherwise indicated, properties are nontunable, which means you cannot change their values after calling the object. Objects lock when you call them, and the release function unlocks them.

If a property is tunable, you can change its value at any time.

For more information on changing property values, see System Design in MATLAB Using System Objects.

Main

Mode — VGA operating mode

1 (default) | 0

VGA operating mode, specified as 0 or 1. Mode determines if the VGA adjusts the gain of input signal or acts as a pass-through.

Mode Value	VGA Mode	VGA Operation
0	Off	serdes.VGA is bypassed, the input waveform remains unchanged.
1	On	serdes.VGA scales the input waveform according to the specified Gain.

Data Types: double

Gain — Multiplicative gain used to scale the input waveform

1 (default) | scalar

Multiplicative gain used to scale the input waveform, specified as a unitless scalar.

Data Types: double

Usage

Syntax

y = vga(x)

Description

y = vga(x)

Input Arguments

x — Input signal

scalar | vector

Input signal to be scaled, specified as a scalar or vector.

Output Arguments

y — Scaled output signal

scalar | vector

Scaled output signal, returned as a scalar or vector corresponding to the input signal.

Object Functions

To use an object function, specify the System object™ as the first input argument. For example, to release system resources of a System object named obj, use this syntax:

release(obj)

Common to All System Objects

step	Run System object algorithm
release	Release resources and allow changes to System object property values and input characteristics
reset	Reset internal states of System object

Examples

Scaling Input Waveform using VGA

This example shows how to apply variable gain to input waveform using serdes.VGA system object™.

Create the input waveform.

t = linspace(0,12,101);
y1 = sin(t);

Create the VGA object with a scale factor of 3.

vga = serdes.VGA('Gain',3);

Process the input waveform with the VGA object.

y2 = vga(y1);

Plot the input and output waveforms.

figure
plot(t,y1,t,y2)
xlabel('Time')
ylabel('Voltage')
legend('Input','output')
grid on
title(sprintf('Scaled Output Waveform Using VGA System Object = %g',vga.Gain))     

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

IBIS-AMI codegen is not supported in MAC.