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serdes.SaturatingAmplifier

Models a saturating amplifier

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Description

The serdes.SaturatingAmplifier System object™ scales the input waveform according to a voltage in versus voltage out response. The voltage in versus voltage out response is specified either by the soft clipping response defined by Limit and Linear Gain properties or by the VinVout property. serdes.SaturatingAmplifier System object applies memoryless nonlinearity to incoming waveform.

To limit the voltage output to a specific value:

  1. Create the serdes.SaturatingAmplifier 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

SatAmp = serdes.SaturatingAmplifier
SatAmp = serdes.SaturatingAmplifier(Name,Value)

Description

SatAmp = serdes.SaturatingAmplifier returns an amplifier object that modifies the input signal so that the output voltage is clipped to 1.2 V.

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

Example: SatAmp = serdes.SaturatingAmplifier('Limit',5) returns a saturating amplifier object that limits the output waveform at 5 V.

Properties

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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.

Amplifier operating mode, specified as 0 or 1. Mode determines whether the amplifier is bypassed or not.

Mode ValueSaturating Amplifier ModeSaturating Amplifier Operation
0Offserdes.SaturatingAmplifier is bypassed and the input waveform remains unchanged.
1Onserdes.SaturatingAmplifier scales the input waveform according to a voltage in versus voltage out response.

Data Types: double

Input specification for limiting amplifier output:

  • 'Limit and Linear Gain' — Creates a soft clipping voltage in versus voltage out response with the values specified in the Limit and Linear Gain properties.

  • 'VinVout' — Generates output voltages corresponding to input voltage specified in the VinVout property. If any input voltage point falls outside the specified values, the output for that particular input voltage is linearly interpolated.

Data Types: char

Clipping voltage for the limiting amplifier, specified as a real positive scalar in V.

Data Types: double

Amplifier gain in the linear region, specified as a unitless real positive scalar.

Data Types: double

Input and corresponding output voltage response table, specified as an N×2 matrix (for 2-D table) or N×2×M matrix (for 3-D table) in volts. N is the number of voltage samples and M is the number of slices.

If VinVout is a 3-D table, you can select which slice of the VinVout is to use. To know more about defining 3-D VinVout matrix, see Define Saturating Amplifier with 3D VinVout Matrix.

Data Types: double

Select which slice, family, or corner of a 3-D VinVout matrix to use during CTLE configuration.

You must set Specification to VinVout to effectively use SliceSelect. Depending on how many slices are available in your VinVout matrix, you can then select the slice you are interested in from a zero-based index.

Data Types: double

Usage

Syntax

y = SatAmp(x)

Description

y = SatAmp(x)

Input Arguments

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Input baseband signal.

Output Arguments

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Clipped output voltage, as specified by the serdes.SaturatingAmplifier object.

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)

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stepRun System object algorithm
releaseRelease resources and allow changes to System object property values and input characteristics
resetReset internal states of System object

Examples

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Open Live Script

This example shows how to clip an incoming sine wave using the serdes.SaturatingAmplifier system object™.

Define an input sine wave with a frequency of 250 Hz.

Fs = 10000;
L = 100;
t = (0:L-1)'/Fs;
x = sin(2*pi*250*t);

Construct the SaturatingAmplifier system object with a linear gain of 2, and gain limit of 0.8 V.

linearGain = 2;
limit = 0.8;
SaturatingAmplifier = serdes.SaturatingAmplifier('Mode',1,...
          'Limit',limit,'LinearGain',linearGain);
y = SaturatingAmplifier(x);

Plot the input and modified waveforms.

figure, plot(t,x,t,y)
legend('Input','Output')
title('Clipping Waveform Using Saturating Amplifier');
xlabel('Time (s)');
ylabel('Amplitude (V)');

Figure contains an axes object. The axes object with title Clipping Waveform Using Saturating Amplifier, xlabel Time (s), ylabel Amplitude (V) contains 2 objects of type line. These objects represent Input, Output.

Open Live Script

This example shows how to define a serdes.SaturatingAmplifier system object™ using the VinVout property.

Define an input sine wave with a frequency of 250 Hz.

t = (0:99)/10000;
x = sin(2*pi*250*t);

Define the Voltage In/Voltage Out matrix.

M = [-0.6194   -0.8000
     -0.4129   -0.6954
     -0.2065   -0.3966
      0         0
      0.2065    0.3966
      0.4129    0.6954
      0.6194    0.8000];

Define the saturating amplifier with the VinVout table.

SatAmp = serdes.SaturatingAmplifier('Mode',1,'Specification','VinVout','VinVout',M);

Modify the input waveform with the saturating amplifier.

y = SatAmp(x);

Plot the input and modified output waveforms.

figure; 
plot (t,x,t,y)
legend ('SaturatingAmplifier input','SaturatingAmplifier output');
grid on;
xlabel('Time (Seconds)');
ylabel('Amplitude (Volts)');

Figure contains an axes object. The axes object with xlabel Time (Seconds), ylabel Amplitude (Volts) contains 2 objects of type line. These objects represent SaturatingAmplifier input, SaturatingAmplifier output.

Open Live Script

Define a 2D VinVout matrix.

LinearGain1 = 1;
Limit1 = 0.7;
N1 = 11;
VinVout1 = serdes.utilities.SoftClipper(LinearGain1, Limit1,N1);

Define a second 2D VinVout matrix.

LinearGain2 = 1.1;
Limit2 = 0.75;
N2 = 7;
VinVout2 = serdes.utilities.SoftClipper(LinearGain2, Limit2,N2);

Combine the two matrices to create a 3D matrix.

VinVout = serdes.SaturatingAmplifier.CombineSlices({VinVout1,VinVout2});

Create a saturating amplifier from the 3D VinVout matrix.

satamp= serdes.SaturatingAmplifier(...
    'Specification','VinVout',...
    'SliceSelect',1,... %Zero-based index
    'VinVout',VinVout);

Extended Capabilities

Version History

Introduced in R2019a

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See Also

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