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8. Real-time Noise Setup

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: -100.00 to 100.00 dB 

Default: 0.00 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 signal generator 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:

N5172 /N5182B: 1.0 Hz to 200.000000000 MHz, in 0.001 Hz steps

N5182A: 1.0 Hz to 125.000000000 MHz, in 0.001 Hz steps

All other models: 1.0 Hz to 80.000000000 MHz, in 1 Hz steps

Default: 1.000 Hz

Specifies the bandwidth over which the noise power is integrated for calculating the carrier to noise ratio (the bandwidth of the target carrier). Also, the maximum upper range is limited to Base Sampling Rate x OSR before download is finished.

Carrier Bandwidth Auto

Choice: Auto | Manual

Default: Manual

Double-click or use the drop-down menu to turn the Manual or AUTO.

When Carrier Bandwidth Auto is Manual, Carrier Bandwidth is available to set a value.

Otherwise it is not available to set a value as read-only.

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:

N5172B/N5182B: 1.0 Hz to 160.0000000 MHz

All other models: 1.0 Hz to 100.0000000 MHz

Default: 1.0 Hz

Set or change the noise bandwidth.

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

Noise Multiplex

Choice: Carrier+Noise | Carrier | Noise

Default: Carrier+Noise

Double-click or use the drop-down menu to select the mode.

This command enables diagnostic control of additive noise, such that only the noise, only the carrier, or the sum of both the noise and the carrier are output from the internal baseband generator. With the ALC off, this feature enables direct measurement of just the carrier or the noise contributions to the total power. The system will still behave as if both the noise and the carrier are present on the output when it comes to determining the Auto Modulation Attenuation and the RMS level for RMS Power Search.

Instrument