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toneBurst

Create an enveloped single frequency tone burst.

Syntax

signal = toneBurst(sample_freq, signal_freq, num_cycles)
signal = toneBurst(sample_freq, signal_freq, num_cycles, ...)

Description

toneBurst creates an enveloped single frequency tone burst for use in ultrasound simulations. If an array is given for the optional input 'SignalOffset', a matrix of tone bursts is created where each row corresponds to a tone burst for each value of the 'SignalOffset'. If a value for the optional input 'SignalLength' is given, the tone burst/s are zero padded to this length (in samples). Several examples are given below.

% return and plot a 1 MHz tone burst with 10 cycles and a Gaussian envelope sampled at 20 MHz
toneBurst(20e6, 1e6, 10, 'Plot', true);

% specify several signals with different temporal offsets
sample_freq          = 20e6;
signal_freq          = 1e6;
num_cycles     	     = 10;
num_ring_up_cycles   = 2;
num_ring_down_cycles = 2;
signal_offsets       = [0, 20, 40];

% create signals
signals = toneBurst(sample_freq, signal_freq, num_cycles, 'Envelope', [num_ring_up_cycles, num_ring_down_cycles], 'SignalOffset', signal_offsets); 

% plot signals
figure;
t_axis = (1:size(signals, 2)) / sample_freq;
stackedPlot(1e6 * t_axis, signals);
xlabel('Time [\mus]');
ylabel('Signal Number');

Inputs

sample_freq sampling frequency [Hz]
signal_freq signal frequency [Hz]
num_cycles number of sinusoidal oscillations

Optional Inputs

Optional 'string', value pairs that may be used to modify the default computational settings.

Input Valid Settings Default Description
'Envelope' 'Gaussian'
'Rectangular'
[num_ring_up_cycles, num_ring_down_cycles]		 'Gaussian' Envelope used to taper the tone burst. The last option generates a continuous wave signal with a cosine taper of the specified length at the beginning and end.
'Plot' (Boolean scalar) false Boolean controlling whether the created tone burst is plotted.
'SignalLength' (integer) 'auto' Signal length in number of samples. If longer than the tone burst length, the signal is appended with zeros.
'SignalOffset' (integer) 0 Signal offset before the tone burst starts in number of samples.

Outputs

signal created tone burst

Examples

See Also

gaussian
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