User manual

Audio Generator

AM700 Audio Measurement Set User Manual

4-33

Because this is an analog bandpass filter, time is required to center the filter during a

sweep. Disabling Distortion Reduction mode switches the bandpass filter out of the

circuit and improves sweep time.

Frequency response sweeps can be performed with no distortion reduction; however,

measuring a signal that has extremely low residual distortion (in which the

distortion of the generator becomes potentially significant) may require selecting

Distortion Reduction mode to reduce generator distortion.

Output Common. Selections are Floating or Ground. Audio entering and exiting the

AM700 is balanced. Under some conditions, it may be useful to break any ground

loops between the AM700 and the load by floating the AM700 audio signal

common. In other situations, for example in high RF environments, it may be

necessary to ground the AM700 common to prevent its floating on RF that can be

induced in output cables.

Output Impedance. Use this field you to select 10 Ω, 150 Ω, or 600 Ω output

impedance. You can also enter the output impedance at the keypad and press Enter

to accept.

NOTE. Entering any number greater than 10 or 150 and pressing Enter causes the

AM700 to substitute the next higher valid impedance value.

HR Dither Type. Selections are None, Rectangular PDF, or Triangular PDF. Dither is

used to reduce truncation noise, but raises the noise floor. The dither selections for

the high resolution generator allow you to choose the type of probability density

functions (PDF) used in dithering. Dithering is not available for the high bandpass

generators.