NI 5402/5406
CH 0 Connector

The CH 0 connector provides the analog waveform output. The maximum output levels from this connector depend on the type of load termination. If the output of the module terminates into a 50 Ω load, the maximum output levels are ±5 V as shown in the following figure.

If the output of the module terminates into a high-impedance load (HiZ), the maximum output levels are ±10 V. If the output terminates into any other load, the levels are as follows:

V_out = ± [ R_L / ( R_L + R_O ) ] × 10 V

Note  For loads less than 50 Ω, load impedance compensation only supports combinations of a gain and load impedance that meet the previous Vout equation.

where

V_out is the maximum peak output voltage level

R_L is the load impedance in ohms

R_O is the output impedance of the module

By default, R_O = 50 Ω, but you can set the output impedance to 75 Ω in NI-FGEN. Refer to the niFgen Configure Output Impedance VI or the niFgen_ConfigureOutputImpedance function for more information about configuring the output impedance.

You can set the amplitude of the generated output signal in terms of peak voltage by setting the gain value. NI-FGEN calculates and sets the correct amount of attenuation required for the desired gain value. Refer to the Amplitude property or the NIFGEN_ATTR_FUNC_AMPLITUDE attribute for more information about configuring the output signal amplitude.

Load Impedance Compensation

The NI 5402/5406 has the ability to configure the output signal amplitude based on a user-configured load-impedance setting. This is desirable for using the NI 5402/5406 with loads that are between 0 Ω and a high impedance. Refer to the module specifications for information about the output impedance tolerance.

By default, NI-FGEN assumes that the load impedance is equal to the output impedance. If they do not match, you have the option to change the load impedance value that NI-FGEN uses in its load-impedance compensation algorithm. NI-FGEN takes the load impedance into account for setting the amplitude, and provides the amplitude specified in the configured gain setting, eliminating the need to use the voltage divider equation. NI-FGEN compensates to give the desired peak-to-peak voltage amplitude. Refer to the Load Impedance property or the NIFGEN_ATTR_LOAD_IMPEDANCE attribute for more information about load impedance.

Note  The voltage output levels are set in the software and are based upon a 50 Ω load termination by default, or based on the load resistance as specified by the user.

For specifications about the waveform output signal, refer to the module specifications.