Sampling Clock Source

Generate clock signal with aperture jitter

• Library:

• 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

clk — Output clock with aperture jitter

scalar

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

Clock type — Output clock signal shape

Square wave (default) | Sine wave

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

• Use get_param(gcb,'SignalType') to view the current Clock type.

• Use set_param(gcb,'SignalType','Square wave') to set Clock type as Square wave.

• Use set_param(gcb,'SignalType','Sine wave') to set Clock type as Sine wave.

Clock frequency (Hz) — Desired frequency of output clock signal

1e6 (default) | scalar

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

Programmatic Use

• Use get_param(gcb,'Freq') to view the current value of Clock frequency.

• Use set_param(gcb,'Freq',value) to set Clock frequency to a specific value.

Clock output range

Min (V) — Minimum clock output voltage

-1 (default) | real scalar

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

Programmatic Use

• Use get_param(gcb,'Min') to view the current value of Min.

• Use set_param(gcb,'Min',value) to set Min to a specific value.

Max (V) — Maximum clock output voltage

1 (default) | real scalar

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

Programmatic Use

• Use get_param(gcb,'Max') to view the current value of Max.

• Use set_param(gcb,'Max',value) to set Max to a specific value.

Impairment

RMS aperture jitter (s) — Standard deviation of clock edge locations

1e-12 (default) | real nonnegative scalar

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

• Use get_param(gcb,'RMSJitt') to view the current value of RMS aperture jitter.

• Use set_param(gcb,'RMSJitt',value) to set RMS aperture jitter to a specific value.

Enable increased buffer size — Enable increased buffer size

off (default) | on

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.

Buffer size — Number of samples of the input buffering available during simulation

5 (default) | positive integer scalar

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

This parameter is only available when Enable increased buffer size option is selected in the Configuration tab.

Programmatic Use

• Use get_param(gcb,'NBuffer') to view the current value of Buffer size.

• Use set_param(gcb,'NBuffer',value) to set Buffer size to a specific value.