Sampling Clock Source

Generate clock signal with aperture jitter

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  • Sampling Clock Source block

Libraries:
Mixed-Signal Blockset / ADC / Building Blocks

Description

The Sampling Clock Source block generates either a sine wave or square wave clock with aperture jitter impairments.

Ports

Output

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Output clock signal with aperture jitter, returned as a scalar. The clock is a periodic pulse train that can be a sine wave or a square wave, based on the Clock type parameter.

Data Types: double

Parameters

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Shape of the output clock signal.

  • Square wave — Returns a square wave of 1 volts amplitude and specified frequency.

  • Sine wave — Returns a sine wave of 1 volts amplitude and specified frequency.

Programmatic Use

Block parameter: SignalType
Type: character vector
Values: Square wave | Sine wave
Default: Square wave

Desired frequency of the output clock signal, specified as a scalar in hertz.

Programmatic Use

Block parameter: Freq
Type: character vector
Values: scalar
Default: 1e6

Minimum voltage of the output clock signal, specified as a real scalar in volts.

Programmatic Use

Block parameter: Min
Type: character vector
Values: real scalar
Default: 0

Maximum voltage of the output clock signal, specified as a real scalar in volts.

Programmatic Use

Block parameter: Max
Type: character vector
Values: real scalar
Default: 1

Standard deviation of clock edge locations, generated by an impaired clock with respect to an ideal clock. RMS aperture jitter is specified as a real nonnegative scalar in seconds.

Aperture delay is the delay between sampling clock signal and the actual instant when the sample is taken. Aperture jitter is the sample to sample variation between aperture delay. Aperture jitter results in an error voltage in ADC that is proportional to the magnitude of the jitter and the slew rate of the input signal to ADC.

Programmatic Use

Block parameter: RMSJitt
Type: character vector
Values: nonnegative real scalar
Default: 1e-12

Advanced

Select to specify a custom seed for generating the clock signal. By default, this option is deselected.

Seed for generating the clock signal, specified as a nonnegative real scalar.

Programmatic Use

Block parameter: Seed
Type: character vector
Values: nonnegative real scalar
Default: 0

Dependencies

To enable this parameter, select Specify custom seed in the Advanced tab.

Select to specify a custom initial output for the sampling clock source. By default, this option is deselected.

The initial output of the sampling clock source, specified as a real scalar.

Programmatic Use

Block parameter: InitialOutput
Type: character vector
Values: real scalar
Default: 0

Dependencies

To enable this parameter, select Specify custom initial output in the Advanced tab.

Select to enable increased buffer size during simulation. This increases the buffer size of the Variable Pulse Delay block inside the Sampling Clock Source block. By default, this option is deselected.

Number of samples of the input buffering available during simulation, specified as a positive integer scalar. This sets the buffer size of the Variable Pulse Delay block inside the Sampling Clock Source block.

Selecting different simulation solver or sampling strategies can change the number of input samples needed to produce an accurate output sample. Set the Buffer size to a large enough value so that the input buffer contains all the input samples required.

Dependencies

To enable this parameter, select Enable increased buffer size in the Advanced tab.

Programmatic Use

Block parameter: NBuffer
Type: character vector
Values: positive integer scalar
Default: 50

Version History

Introduced in R2019a

See Also

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