5.2.2. Period setting
Press
【
Period
】
key, the light of which will be on, press “s” unit to display present period value, input period
value with numeric keys or adjusting knob. Frequency is synthesized in the internal of the generator, and
converted to period when inputting and displaying. Limited by the frequency low resolution, for a
comparatively long period, the generator could only output some frequency points with long period interval,
so the period of actual output signal may be comparatively different from them, which should be under
consideration during operations.
5.2.3 Amplitude setting
Press
【
Ampl
】
key, the light of which will be on, press “Vpp” or “Vrms” to display present amplitude value,
input amplitude value with numeric keys or adjusting knob and the signals of this amplitude will be output
from the output port.
The relation between maximum amplitude and DC offset value should be below formula, if the setting of
amplitude exceeds specification, the generator will modify it until it is within the range of allowed maximum
amplitude value.
Vpp
≤
2 × (10-|offset|)
5.2.4 Amplitude value form
There are two forms for amplitude input and display: peak-peak form and RMS form. Press
【
Vpp
】
or
【
mVpp
】
to input amplitude peak-peak value after inputting the digits, press
【
Vrms
】
or
【
mVrms
】
to input
amplitude RMS value. RMS value is applicable only to sinewave, square wave, Ramp wave and pulse wave
four common waveforms, and other waveforms could only be shown by amplitude peak-peak value.
5.2.5. Amplitude attenuation setting
Press
【
Ampl
】
key and select “Atten” option to show the present attenuation value. Amplitude attenuation is
auto as default of booting and there display “Auto”, the generator will select automatically proper attenuation
proportion according to the amplitude setting value, higher amplitude resolution, higher signal-noise ratio and
less waveform distortion could be realized at the same time regardless of the amplitude magnitude of the
signal. The output signal makes a momentary hop when the attenuation changes, which is not welcome in
some operations, but the generator has fixed attenuation function to avoid this circumstance. Input
attenuation values of 0dB, 20dB, 40dB and 60dB with the numeric keys, input 80dB to select auto
attenuation. Users may use the adjusting knob as well, the attenuation changes to next one for every step of
the rotation. When select fixed attenuation mode, the attenuation is fixed while the signal amplitude changes,
and the output signal could changes continuously within the whole amplitude range. But higher distortion of
the waveform and poor signal-noise ratio maybe appear when the attenuation is 0dB and the amplitude of
the signal is small.
5.2.6. Output load
The setting value of amplitude is calibrated when the output end is open. The real voltage of output load is
the setting value of amplitude multiplied by the assignment ratio of load impedance and output impedance.
The output impedance of the generator is fixed at 50
Ω
. When the load impedance is high enough, the
assignment ratio approaches to 1. The voltage loss of output impedance can be neglected. The real voltage
approaches to the setting value of amplitude. But when the load impedance is lower, the voltage loss of
output impedance cannot be neglected. It should be paid more attention that the real voltage does not
accord with the setting value of amplitude. Especially when the frequency is comparatively high, the output
and the change of inductance and condensance on the load will cause a comparatively large error.
With 50
Ω
output resistance, a momentary short-circuit of the output port makes no damage to the generator,
but the users should try to avoid long time short-circuit under high voltage output as a danger of making
damage to the generator. The generator has function of opposite voltage protection, with which the generator
close output automatically, make an alarm with the output indicating light off when carelessly connect a high
voltage(less than 30V) to the output port. Open the output by pressing
【
Output
】
key only after the fault
cleared.
-11-
