NF WF1943B - Operating Principles; Block Diagram

WF1943B 1-3
1.2 Operating principles
 Block diagram
Display and panel key
Waveform memory
Amplitude control
occurrence
Others
TRIG/
SWEEP
IN
GPIB
Ｄ／Ａ ＬＰＦ

ＤＤＳ
ＣＰＵ

ＡＴＴ

Clock
Offset D/A
SYNC OUT
14bit
16bit
OUT
FUNCTION
Over level
Detector
USB
Isolation
z The CPU conducts analog control for display, panel keys, remote control (GPIB, USB), DDS,
amplitude and DC offset. Sweep/internal modulation are also conducted.
z The clock generator produces DDS reference and CPU clock signals.
z An isolation circuit between the CPU and DDS provides floating functions.
z The DDS (Direct Digital Synthesizer) uses an original LSI device and generates digital data of
the setting frequency.
z The waveform memory converts digital data from the DDS into standard or arbitrary waveform
data. Waveform data are set from the CPU.
z The digital to analog (D/A) converter produces an analog signal from the resulting waveform
data.
z The lowpass filter (LPF) smoothes the stepped D/A output signal.
z Amplitude control is set by the gain control. DC offset is produced by the offset D/A converter
and the output amplifier adds and amplifies the output signal.
z The attenuator (ATT) selects the output range by 1/10 attenuation on/off.