NF DF 1906, Инструкция по эксплуатации

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1.4 Operating Principle
DF1906
1-4
1.4 Operating Principle
Figure 1-1 Block Diagram
・
CPU performs analog control, such as display panel control, panel key and dial process, US B
remote control process, DDS control, amplitude, and DC offset.
・
DDS (Direct Digital Synthesizer) generates digital data at the set frequency.
・
Waveform Memory converts the digital data from the DDS to standard waveform or arbitrar y
waveform data.
The waveform data is set from the CPU. The update rate of waveform data is approx. 6.872 MHz.
・
The waveform data acquired in this way is converted to an analog s ignal by the D/A converter.
・
LPF (Low Pass Filter) smoothens a staircase waveform output by the D/A converter.
The analog bandwidth (at the -3dB) for arbitrary waveforms and sine wave and ramp wave in the
burst/trigger/gate oscillation mode is approx. 650 kHz.
・
For a square wave at a duty ratio of 50% and at a frequency of 10 kHz or more, a low jitter squar e
wave is obtained by generating a sine wave by the Waveform Memory- D/A Converter-LPF and
converting it to a square wave by an analog comparator in the gener ator.
・
For a square wave at a duty ratio of other than 50% or at a frequency of less than 10 kHz, a logic
signal with a duty var iable pulse generated by the DDS is converted to a squar e wave by the
gener ator. This includes a one-c lock (approx. 150 ns) jitter of the DDS.
・
The amplitude is set in the amplitude controller. The DC gener ator generates a DC offset, which is
added and amplif ied in the output amplif ier to output a signal.
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TRIG IN
SYNC OUT
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DDS