bud_noise_pwr()

Returns the budget noise power

Syntax
y = bud_noise_pwr(Zref, Plan, pinNumber, "simName")

Arguments

Examples

x = bud_noise_pwr()
returns the noise power at all frequencies
y = bud_noise_pwr(75, 1)
returns the noise power at reference frequencies in plan 1

Defined in

$HPEESOF_DIR/expressions/ael/budget_fun.ael

See Also

bud_pwr()

Notes/Equations

Used in AC and harmonic balance simulations
This is the noise power (in dBm) at the terminal(s) of each component, looking into the component. If Zref is not specified, the impedance that relates the signal voltage and current is used to calculate the noise power. Note that the fundamental frequency at different pins can be different, and therefore values are given for all frequencies unless a Plan is referenced.

Note Remember that the budget function can refer only to the default dataset, that is, the dataset selected in the data display window.

This function does not have the bandwidth parameter, so the results rely entirely on the setting of the bandwidth in the Noise tab of the simulation controller.
For AC noise and budget calculations, the bandwidth parameter flatly scales the noise voltages, and consequently noise powers, SNR, etc., regardless of the frequency response.
If you make a frequency sweep then the narrow band noise voltages properly follow the frequency characteristic of the circuit and are presented as a function of the swept frequency values. However, changing the bandwidth in the simulator controller would again just flatly rescale all the values, regardless of whether the frequency response remains flat or changes drastically over the (local) bandwidth, or whether the adjacent bands overlap or not.
The only true integration over a bandwidth is done for the phase noise (as one of the options in the NoiseCon controller).

A work-around solution is to do an appropriately wide frequency sweep setting the bandwidth value in the AC controller to that of the frequency step. Then adding all the powers (need to be first converted from dBm to watts) would do the integration.

Budget Path Measurements

Instead of all components in alphabetical order, this function can report its values just for the components selected in a budget path, and following the sequence in that path. To facilitate the budget path measurements the name of the budget path variable, as defined in the Schematic window, needs to be entered as the pinNumber argument.