NF wf1966, Instruction Manual

Page: 15 / 198

WF1966
1-3
1.2 Operating principles
„
Block diagram
16bit
14bit
CPU DDS
D/
A
LP
F
ATT
SYNC OUT
AM IN
ADD IN
FUNCTION OUT
GPIB
USB
Disp
lay a
nd
p
an
el key
W
avef
or
m
m
em
ory
Others
occurrence
Am
pli
tude con
tro
l
Multipl
ier
Clock
Synchronized operation
input/output
Isolation
Offset
D/A
Over level
Detector
CH 2
CH 1
TRIG/SWEEP
IN
Sweep
input/output
z The CPU conducts analog control for display, panel keys, remote control (GPIB, USB), DDS,
amplitude and DC offset. Sweep/internal modulation and sweep input/output control are also
conducted.
z
The clock generator produces DDS reference and CPU clock signals.
z
Two sets of circuits for DDS and analog compose two channels.
z
An isolation circuit is inserted between the CPU and DDS, causing the analog circuit to float.
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.