Real Time

8. Real-time Noise Setup (Signal Generators only)

Instrument: 1 2 3 4 5 6 7 8 9        

The following figure is a composite of all supported instruments, so some parameters may not apply to your instrument.

If an instrument does not have Real-time Noise capabilities, the noise effect does not work.

Real-time Noise

Choice: On | Off

Default: Off

Double-click or use the drop-down menu to enable or disable adding real-time, non-repeating additive white Gaussian noise (AWGN) to the carrier being modulated by the waveform being played.

On – enables the addition Real-time Noise.

Off – disables the addition of Real-time Noise.

Carrier to Noise Ratio

Range: –100 to 100 dB

Default: 30 dB 

Enter the noise power to be applied to a waveform. The carrier power is defined as the total modulated signal power before noise power is added. When you add noise, the power output from the instrument does not change; it is the sum of carrier power and the added noise power. A positive value makes C larger than N.

Carrier Bandwidth

Range:

N5182A : 1.00 Hz to 125.00 MHz

N5172B, Opt 653 : 1.00 Hz to 60.00 MHz

N5172B, Opt 655: 1.00 Hz to 120.00 MHz

N5182B, Opt 656: 1.00 Hz to 80.00 MHz

N5182B, Opt 657: 1.00 Hz to 160.00 MHz

E4438C : 1.00 Hz to 80.00 MHz

E8267D : 1.00 Hz to 80.00 MHz

Default:

270.833 kHz

Specifies the bandwidth over which the noise power is integrated for calculating the carrier to noise ratio (the bandwidth of the target carrier).

Noise Bandwidth Factor

Range: 1 to 2

Default: 1

Displays the flat noise bandwidth factor for the applied real-time noise.

When the Sample Clock is < 50 MHz, the Noise Bandwidth Factor adjusts the RF flat noise bandwidth to be either at least 0.8 times the sample rate for a bandwidth factor of 1, or 1.6 times the sample rate if the bandwidth factor is 2.

When the Sample Clock is > 50 MHz, noise cannot be enabled if the Noise Bandwidth Factor is 2. Any oversampling in a waveform will effectively make the noise bandwidth that many times wider than the signal bandwidth.

The Noise Bandwidth is calculated as follows:

The noise bandwidth is at least 0.8 * [ARB Sample Clock] * [Noise Bandwidth Factor]

This parameter is not available for all instrument model numbers and may be grayed out.

Noise Bandwidth

Range: 1.00 Hz to 100.000 MHz

Default: 500 kHz

Set or change the noise bandwidth (MHz).

This parameter is not available for all instrument model numbers and may be grayed out.