DiscreteSignalSum#

class DiscreteSignalSum(dt, samples, start_time=0.0, carrier_freq=None, phase=None, name=None)[source]#

Bases: DiscreteSignal, SignalSum

Represents a sum of piecewise constant signals, all with the same time parameters: dt, number of samples, and start time.

Directly initialize a DiscreteSignalSum. Samples of all terms in the sum are specified as a 2d array, with 0th axis indicating time, and 1st axis indicating a term in the sum.

Parameters:

  • dt (float) – The duration of each sample.

  • samples (Union[ndarray, number, int, float, complex, Tracer, Array, Array, spmatrix, BCOO, list]) – The 2d array representing a list whose elements are all envelope values at a given time.

  • start_time (float) – The time at which the signal starts.

  • carrier_freq (Union[ndarray, number, int, float, complex, Tracer, Array, Array, spmatrix, BCOO, list]) – Array with the carrier frequencies of each term in the sum.

  • phase (Union[ndarray, number, int, float, complex, Tracer, Array, Array, spmatrix, BCOO, list]) – Array with the phases of each term in the sum.

  • name (str) – name of the signal.

Methods

add_samples(start_sample, samples)#

Appends samples to the pulse starting at start_sample, filling any gap with zeros.

Parameters:

  • start_sample (int) – Index of the sample at which the new samples should be appended.

  • samples (List) – List of samples to append.

Raises:

QiskitError – If start_sample is less than the current length of samples.

complex_value(t)#

Return the sum of the complex values of each component.

Return type:

Union[ndarray, number, int, float, complex, Tracer, Array, Array, spmatrix, BCOO, list]

conjugate()#

Return the conjugation of this collection.

draw(t0, tf, n, function='signal', axis=None, title=None)#

Plot the signal over an interval.

The function arg specifies which function to plot:

  • function == 'signal' plots the full signal.

  • function == 'envelope' plots the complex envelope.

  • function == 'complex_value' plots the complex_value.

Parameters:

  • t0 (float) – Initial time.

  • tf (float) – Final time.

  • n (int) – Number of points to sample in interval.

  • function (Optional[str]) – Which function to plot.

  • axis (Optional[axis]) – The axis to use for plotting.

  • title (Optional[str]) – Title of plot.

envelope(t)#

Vectorized evaluation of the envelope at time t.

Return type:

Union[ndarray, number, int, float, complex, Tracer, Array, Array, spmatrix, BCOO, list]

flatten()#

Merge into a single Signal. The output frequency is given by the average.

Return type:

Signal

classmethod from_Signal(signal, dt, n_samples, start_time=0.0, sample_carrier=False)#

Constructs a DiscreteSignal object by sampling a Signal.

The optional argument sample_carrier controls whether or not to include the carrier in the sampling. I.e.:

  • If sample_carrier == False, a DiscreteSignal is constructed with:

    • samples obtained by sampling signal.envelope.

    • carrier_freq = signal.carrier_freq.

    • phase = signal.phase.

  • If sample_carrier == True, a DiscreteSignal is constructed with:

    • samples obtained by sampling signal (as a callable)

    • carrier_freq = 0.

    • phase = signal.phase.

In either case, samples are obtained from the midpoint of each interval.

Parameters:

  • signal (Signal) – Signal to sample.

  • dt (float) – Time increment to use.

  • n_samples (int) – Number of steps to resample with.

  • start_time (Optional[float]) – Start time from which to resample.

  • sample_carrier (Optional[bool]) – Whether or not to include the carrier in the sampling.

Returns:

The discretized Signal.

Return type:

DiscreteSignal

classmethod from_SignalSum(signal_sum, dt, n_samples, start_time=0.0, sample_carrier=False)[source]#

Constructs a DiscreteSignalSum object by sampling a SignalSum.

The optional argument sample_carrier controls whether or not to include the carrier in the sampling. I.e.:

  • If sample_carrier == False, a DiscreteSignalSum is constructed with:

    • samples obtained by sampling signal_sum.envelope.

    • carrier_freq = signal_sum.carrier_freq.

    • phase = signal_sum.phase.

  • If sample_carrier == True, a DiscreteSignal is constructed with:

    • samples obtained by sampling signal_sum (as a callable)

    • carrier_freq = 0.

    • phase = signal_sum.phase.

In either case, samples are obtained from the midpoint of each interval.

Parameters:

  • signal_sum (SignalSum) – SignalSum to sample.

  • dt (float) – Time increment to use.

  • n_samples (int) – Number of steps to resample with.

  • start_time (Optional[float]) – Start time from which to resample.

  • sample_carrier (Optional[bool]) – Whether or not to include the carrier in the sampling.

Returns:

The discretized SignalSum.

Return type:

DiscreteSignalSum

Attributes

carrier_freq#

The carrier frequency of the signal.

components#

The list of components.

dt#

Returns: dt: the duration of each sample.

duration#

Returns: duration: The duration of the signal in samples.

is_constant#

Whether or not the signal is constant.

name#

Return the name of the signal.

phase#

The phase of the signal.

samples#

Returns: samples: the samples of the piecewise constant signal.

start_time#

Returns: start_time: The time at which the list of samples start.