User Manual

4.2.2. Setting of period:
* The signal can also be set and displayed in the form of period. Press the key of 【Period】. The current
period value will be displayed. Then use the numeric keys or the knob to enter the period value. But
frequency synthesizing way is still used in the interior of the generator. It is only a conversion when
entering and displaying the data. Limited by the low-end resolution of frequency, only those frequency
points with large distant period can be entered for longer periods. Although the setting and display of the
period are accurate, the period values of real output signal will be greatly different.
4.2.3. Setting of amplitude:
* Press the key of 【Ampl】 and the current amplitude will be displayed. Then use the numeric keys or the
knob to enter the amplitude value. The amplitude will be output at the end of “Output”.
* The relation between maximum amplitude and 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|)
4.2.4. Format of amplitude value:
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 and ramp wave, and other waveforms could only be shown by amplitude peak-peak value.
4.2.5. Amplitude attenuator:
* The generator is set to “Auto” when startup. Press the key of【Atten】. Then the generator selects the
attenuation proportion automatically according to the magnitude of the set amplitude. The attenuation
switches when the output amplitudes are 2Vpp, 0,2Vpp and 0,02Vpp. Now, higher amplitude resolution
and signal-to-noise can be obtained regardless of the magnitude of amplitude.
The distortion of waveform is smaller. But a little instant jumping will occur for output signal when
attenuation switching, which is not allowed in some cases. So the fixed attenuation way is set for the
generator. Pressing the key of 【Atten】, the attenuation value can be entered by the numeric keys. The
attenuation is 0dB, 20dB, 40dB and 60dB. The knob can also be used to adjust the attenuation. The
attenuation will change one gear for each step. If the fixed attenuation way is selected, the attenuation step
will not be changed when the amplitude of signal changes So that the output signal within the whole
amplitude range will be changed continually. But if the amplitude of signal is small in the attenuation of
0dB, the distortion of waveform will be larger and the signal-to-noise ratio is worse.
4.2.6. 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, including
inductance and condensance and output impedance. The output resistance is about 50. When the load
resistance is big enough, the assignment ratio approaches to 1. The voltage loss of output resistance can
be neglected. The real voltage approaches to the setting value of amplitude. But when the load resistance
is smaller, the voltage loss of output resistance cannot be neglected. It should be paid more attention that
the real voltage does not accord with the setting value of amplitude.
* With 50Ω 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 30 V) to the output port. Open the output by pressing
【Output】key only after the fault cleared.
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