User manual

14
Modulation In Connector
5V p-p signal for 100% modulation, 10Kohms input impedance with DC - >20 KHz bandwidth.
3.5 Output Connections
The waveform generator output circuits operate as a 50 Ω voltage source working into a 50 Ω
load. At higher frequencies, non terminated or improperly terminated output causes
aberrations on the output waveform. In addition, loads less than 50 Ω reduce the waveform
amplitude, while loads more than 50 Ω increase waveform amplitude.
Excessive distortion or aberrations caused by improper termination are less noticeable at
lower frequencies, especially with sine and triangle waveforms. To ensure waveform integrity,
follow these precautions:
1. Use good quality 50 Ω coaxial cable and connectors.
2. Make all connections tight and as short as possible.
3. Use good quality attenuators if it is necessary to reduce waveform amplitudes applied to
sensitive circuits.
4. Use termination or impedance-matching devices to avoid reflections.
5. Ensure that attenuators and terminations have adequate power handling capabilities.
If there is a DC voltage across the output load, use a coupling capacitor in series with the
load. The time constant of the coupling capacitor and load must be long enough to maintain
pulse flatness.
Impedance Matching
If the waveform generator is driving a high impedance, such as a 1 MΩ input impedance
(paralleled by a stated capacitance) of an oscilloscope vertical input, connect the transmission
line to a 50 Ω attenuator, a 50 Ω termination and to the oscilloscope input. The attenuator
isolates the input capacitance of the device and terminates the waveform generator properly.
3.6 MENU Keys
These keys select the main menus for displaying or changing a parameter, function, or mode.
3.6.1 WAVEFORM Keys
These keys select the waveform output and display the waveform parameter menu
(frequency, amplitude and offset).