Agilent Technologies 8935 Series Especificações descarregar pdf (Página 295)

294 Chapter 10

Block Diagrams

Audio Analyzer Section

Input Level Control

Switchable gain amplifiers on the A2A80 Audio Analyzer #1 (see Figure

10-7 on page 295) and A2A40 Audio Analyzer #2 (see Figure 10-8 on

page 296) assemblies keep the audio input signal within a range

suitable for the detectors.

AC and DC Level Measurements

Detected voltages from the Peak+, Peak −, and RMS detectors are

measured on the A2A33 Measurement assembly. The Controller

calculates the displayed value taking into account the detector selected

from the front panel, the gain of the amplifiers, and the source of the

input signal (demodulators, front panel).

Distortion and SINAD Measurements

Distortion and SINAD can be measured on 300 Hz to 10 kHz audio

signals. The Controller calculates distortion and SINAD by comparing

the ratio of the voltage after the variable notch filter to the ratio of the

voltage before the notch filter.

Oscilloscope Functions

The Test Set has no specialized oscilloscope assemblies. The A2A80 and

A2A40 Audio Analyzer assemblies, A2A33 Measurement assembly, and

the Controller work together to perform the oscilloscope functions.

The audio or dc signal to be displayed goes from the A2A40 Audio

Analyzer 2 assembly to a sampler on the A2A33 Measurement

assembly (the same sampler used by the Spectrum Analyzer). The

Controller calculates the display level by taking the value of the

measured signal at each point of the sweep, the gain of the signal path

in the Audio Analyzer assemblies, and the volts-per-division setting.

The oscilloscope’s trigger signals from the side-panel connector, the

A2A32 Signaling Source/Analyzer assembly, and the internal trigger

signal are used by the A2A33 Measurement assembly and the

Controller to determine when to start the scope sweep. The Controller

adds the pre-triggering time entered from the front panel.

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Agilent Technologies 8935 Series Especificações Página 295