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frequencyOffset

Apply frequency offset to input signal

Description

example

y = frequencyOffset(x,samplerate,offset) applies the specified frequency offset to the input signal x.

Examples

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Generate a rectangular 16-point quadrature amplitude modulated (16-QAM) signal by modulating a vector of input data.

M = 16;
data = (0:M-1)';
x = qammod(data,M);

Specify the signal sample rate and the frequency offset to apply.

samplerate = 1;
offset = 100e3;

Apply the frequency offset to the input signal.

y = frequencyOffset(x,samplerate,offset);

Define parameters to configure the signal and spectrum analyzer.

fc = 1e6;         % Carrier frequency (Hz)
fs = 4e6;         % Sample rate (Hz)
Nspf = 6e6;       % Number of samples per frame
freqSpan = 400e3; % Frequency span for spectrum computation (Hz)

Create sine wave and spectrum analyzer objects with the specified parameter values.

sinewave = dsp.SineWave(Amplitude=1, ...
    Frequency=fc, ...
    SampleRate=fs, ...
    SamplesPerFrame=Nspf, ...
    ComplexOutput=true);
spectrumscopeRBW1 = dsp.SpectrumAnalyzer( ...
    NumInputPorts=2, ...
    SampleRate=fs, ...
    FrequencySpan="Span and center frequency", ...
    CenterFrequency=fc, ...
    Span=freqSpan, ...
    RBWSource="Property", ...
    RBW=1, ...
    SpectrumType="Power density", ...
    SpectralAverages=10, ...
    SpectrumUnits="dBW", ...
    ShowLegend=true, ...
    ChannelNames={'Input sine wave', 'Frequency-offset sine wave'}, ...
    YLimits=[-50 10]);

Generate a sine wave signal.

x = sinewave();

Apply a frequency offset of 100 kHz to the signal.

offset = 100e3;
y = frequencyOffset(x,fs,offset);

Display the input and frequency-shifted signals by using the spectrum analyzer.

spectrumscopeRBW1(x,y)

Figure Spectrum Analyzer contains an axes object and other objects of type uiflowcontainer, uimenu, uitoolbar. The axes object contains 2 objects of type line. These objects represent Input sine wave, Frequency-offset sine wave.

Input Arguments

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Input signal, specified as a column vector or matrix.

Data Types: double | single
Complex Number Support: Yes

Sampling rate of the input signal in Hz, specified as a positive scalar.

Data Types: double

Frequency offset in Hz, specified as a scalar or row vector.

  • If offset is a scalar, the function applies the same frequency offset to each channel.

  • If offset is a vector, then each element specifies the frequency offset that the function applies to the corresponding column (channel) of the input signal. The number of elements in offset must equal the number of columns in x.

Data Types: double

Output Arguments

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Output signal, returned as a vector or matrix with the same dimensions and data type as x. The number of columns in y corresponds to the number of channels.

Data Types: double | single
Complex Number Support: Yes

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2022a