Voltage Source
Voltage source with optional DC, AC and noise components.
Description
The Voltage Source block is a voltage source model with DC, AC and noise components. The voltage at the + and - terminals is set:
,
where:
-
- DC voltage component.
-
- amplitude of the AC voltage component.
-
- frequency of the AC voltage component.
-
- phase shift of the ac voltage component.
-
- noise voltage.
You can configure the Voltage Source block as a DC only source, AC only source, or a combination of both. By default, both AC and DC components are 0. Define the AC/DC voltage by specifying non-zero parameter values after placing the block in the model.
The noise component is also optional. If you select the check box for Noise mode, the added noise voltage will be defined as follows:
Where:
-
- is the power spectral density of one-way noise for a 1 ohm load, in V^2/Hz.
-
- random number with zero mean and unit standard deviation.
-
- period of generation of noise values.
By default, the Noise mode checkbox is unchecked and the voltage source does not generate thermal noise.
Noise parameters
The unit generates noise according to a normal distribution using a random number generator. You can influence the random number generation by adjusting the Repeatability parameter:
-
Not repeatable- every time you simulate the model, the block will re-generate a seed using the random number generator.
-
Specify seed- when this option is selected, the optional Seed parameter allows you to specify the seed directly.
Parameters
DC & AC Components
DC voltage - output DC voltage
`0 (By default)
Output DC voltage. Specify a non-zero value to add a DC component to the voltage source.
AC voltage peak amplitude - AC voltage peak amplitude
`0 (By default)
The amplitude of the output AC voltage. Specify a non-zero value to add an AC voltage component to the voltage source.
AC voltage phase shift - AC voltage phase shift
`0 (By default)
AC voltage phase shift.
AC voltage frequency - AC voltage frequency
50 Hz (By default).
Frequency of the output AC voltage.
Noise
Enable noise mode - Noise enabled
off (By default) | on
Select the check box to enable noise.
Dependencies
Selecting the Enable noise mode check box opens the related parameters.
Power spectral density - power spectral density
`0 (By default)
One-way noise spectral power. Density function for the square of the voltage, usually considered as the power in a 1 ohm load. To avoid ambiguity in units of measurement, some specifications define noise voltage as noise density in units of V/√Hz. In this case, enter the square of the noise density specified in the specification as the parameter value.
Dependencies
To use this parameter, select the Enable noise mode checkbox.
Repeatability - random number sampling control
Not repeatable (By default) | Specify seed.
To control the generation of random numbers, set this parameter to the following value:
-
Not repeatable- the seed of the random generator changes every time you simulate the model.
-
Specify seed- allows you to specify explicit value of seed using Seed parameter.
Dependencies
To use this parameter, select the Enable noise mode checkbox.
Seed - seed of random number generation
0 (By default)
Seed used by the pseudorandom number generator. The initial value must be 0 or a positive integer.
Dependencies
To use this parameter, select the Enable noise mode checkbox and the Specify seed value for the Repeatability parameter.
Sample time - period of generation of noise values
1e-3 s (By default).
Defines the frequency of random number generation for the noise source. Set this value to reflect the frequencies of interest in your model. Too small an interval between calculation steps will slow down the simulation unnecessarily.
Dependencies
To use this parameter, select the Enable noise mode checkbox.