Main Content

phased.ReceiverPreamp

Receiver preamp

Description

The ReceiverPreamp System object™ implements a model of a receiver preamplifier. The object receives incoming signals, multiplies them by the amplifier gain and divides by system losses. Finally, Gaussian white noise is added to the signal.

To model a receiver preamp:

  1. Define and set up your receiver preamp. See Construction.

  2. Call step to amplify the input signal according to the properties of phased.ReceiverPreamp. The behavior of step is specific to each object in the toolbox.

Note

Starting in R2016b, instead of using the step method to perform the operation defined by the System object, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.

Construction

H = phased.ReceiverPreamp creates a receiver preamp System object, H.

H = phased.ReceiverPreamp(Name,Value) creates a receiver preamp object, H, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

Properties

Gain

Gain of receiver

A scalar containing the gain (in decibels) of the receiver preamp.

Default: 20

LossFactor

Loss factor of receiver

A scalar containing the loss factor (in decibels) of the receiver preamp.

Default: 0

NoiseMethod

Noise specification method

Specify how to compute noise power using one of 'Noise power' | 'Noise temperature'. If you set this property to 'Noise temperature', complex baseband noise is added to the input signal with noise power computed from the ReferenceTemperature, NoiseFigure, and SampleRate properties. If you set this property to 'Noise power', noise is added to the signal with power specified in the NoisePower property.

Default: 'Noise temperature'

NoiseFigure

Noise figure of receiver

A scalar containing the noise figure (in decibels) of the receiver preamp. If the receiver has multiple channels/sensors, the noise figure applies to each channel/sensor. This property is only applicable when you set the NoiseMethod property to 'Noise temperature'.

Default: 0

ReferenceTemperature

Reference temperature of receiver

A scalar containing the reference temperature of the receiver (in kelvin). If the receiver has multiple channels/sensors, the reference temperature applies to each channel/sensor. This property is only applicable when you set the NoiseMethod property to 'Noise temperature'.

Default: 290

SampleRate

Sample rate

Specify the sample rate, in hertz, as a positive scalar. This property is only applicable when you set the NoiseMethod property to 'Noise temperature'. The SampleRate property also specifies the noise bandwidth.

Default: 1e6

NoisePower

Noise power

Specify the noise power (in Watts) as a positive scalar. This property is only applicable when you set the NoiseMethod property to 'Noise power'.

Default: 1.0

NoiseComplexity

Noise complexity

Specify the noise complexity as one of 'Complex' | 'Real'. When you set this property to 'Complex', the noise power is evenly divided between real and imaginary channels. Usually, complex-valued baseband signals require the addition of complex-valued noise. On occasion, when the signal is real-valued, you can use this option to specify that the noise is real-valued as well.

Default: 'Complex'

EnableInputPort

Add input to specify enabling signal

To specify a receiver enabling signal, set this property to true and use the corresponding input argument when you invoke step. If you do not want to specify a receiver enabling signal, set this property to false.

Default: false

PhaseNoiseInputPort

Add input to specify phase noise

To specify the phase noise for each incoming sample, set this property to true and use the corresponding input argument when you invoke step. You can use this information to emulate coherent-on-receive systems. If you do not want to specify phase noise, set this property to false.

Default: false

SeedSource

Source of seed for random number generator

Specify how the object generates random numbers. Values of this property are:

'Auto'The default MATLAB® random number generator produces the random numbers. Use 'Auto' if you are using this object with Parallel Computing Toolbox™ software.
'Property'The object uses its own private random number generator to produce random numbers. The Seed property of this object specifies the seed of the random number generator. Use 'Property' if you want repeatable results and are not using this object with Parallel Computing Toolbox software.

Default: 'Auto'

Seed

Seed for random number generator

Specify the seed for the random number generator as a scalar integer between 0 and 232–1. This property applies when you set the SeedSource property to 'Property'.

Default: 0

Methods

resetReset random number generator for noise generation
stepReceive incoming signal
Common to All System Objects
release

Allow System object property value changes

Examples

collapse all

This example shows how to use the phased.ReceiverPreamp System object™ to amplify a sine wave.

Create a phased.ReceiverPreamp System object with a sample rate of 100 Hz. Assume a receiver noise figure of 60 dB.

fs = 100;
receiver = phased.ReceiverPreamp('NoiseFigure',60, ...
    'SampleRate',fs,'NoiseComplexity','Real');

Create the input signal.

t = linspace(0,1-1/fs,100);
x = 1e-6*sin(2*pi*5*t);

Amplify the signal and compare it with the input signal.

y = receiver(x);
plot(t,x,t,real(y))
xlabel('Time (s)')
ylabel('Amplitude')
legend('Input signal','Amplified signal')

References

[1] Richards, M. A. Fundamentals of Radar Signal Processing. New York: McGraw-Hill, 2005.

[2] Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGraw-Hill, 2001.

Extended Capabilities

Version History

Introduced in R2011a