Wavetek 171 - Page 6

SECTION
I
INTRODUCTION
1.1
THE MODEL
171
The
Wavetek Model
171 Synthesizer/Function
Generator is
a
precision source
of sine, triangle
and square waveforms
and
dc
voltage. The
generator
combines the precision fre-
quency of
a
synthesizer
with the versatility and operating
convenience
of a function
generator.
The two major modes
of operation are synthesizer
and
function generator.
Function generator output
frequency
can be
varied from
0.1 Hz
to
2 MHz in
seven ranges
manually
by
dial
and re-
motely by an applied voltage.
In addition
to
this analog
control of frequency, the
Model 171
has a 414
digit switch
for synthesizer
control
of function generator frequency._
The synthesizer
gives precision
(0.005%)
frequency accuracy
and
stability
(0.0001%/°C)
from
1.000 Hz
to 1.9999 MHz
in six
ranges.
When
the synthesizer
is used
to
set
the fre-
quency, in
addition to greater frequency
accuracy and sta-
bility,
the
waveform
purity is
improved over
that
of
the
function generator alone.
Amplitude of
the waveform
is
continuously variable from
10V peak-to-peak
in
a matching
termination load
(500
or
6000)
down
to
10 mV
peak-to-peak in four ranges of
at-
tenuation
(0,
20, 40, 60 dB). DC reference of the waveforms
can
be
offset positively
and negatively.
The synthesizer can
be locked
to
its own internal
reference or
to an external
1 MHz reference.
1.2 SPECIFICATIONS
The available waveforms,
frequencies,
amplitudes, operating
modes, precision (accuracy)
and purity (quality)
are listed
in the following
paragraphs.
1.2.1 Versatility
Output Signals
Sine
'X,
,
triangle
\
,
square
n
u
and DC selectable.
TTL
pulse
J"i
,
1 MHz reference
pulse JT and
GCV
signal
proportional to output frequency
are also available.
Control
Generator
operates
in
continuous
mode. Frequency
is
controlled manually
by dial or digital switch,
or externally
thru
VCG input voltage. Digital
switch
is
operable
between
0.1000 and
1.9999 settings
and works with all
frequency
multipliers except
X 1.
Frequency
Range
0.1 Hz
to 2 MHz in seven overlapping ranges.
Operating
Frequency Ranges
FREQ MULT
Range Digital Resolution
X
1 0.1
Hz
to 2 Hz N. A.
X 10
0.1
Hz
to 20
Hz
0.001 Hz
X 100
0.2
Hz
to 200 Hz
0.01
Hz
X IK 0.2
Hz
to 2
kHz
0.1 Hz
X 10K 20 Hz to 20 kHz
1.0
Hz
X 100K 200
Hz
to
200
kHz
10 Hz
X 1M 2
kHz
to 2
MHz
100 Hz
NOTE
Digital switch valid
with all frequency
multipliers
except X
1
(first
range). Frequency
ratio of
1000:1 on dial,
20:1 on digital switch.
Main Output
\i
,
\
,
T-i
;
variable
to 20V
p-p
into open circuit and
10V
p-p
with matching
load
at
either
500 OUT or 6000
OUT. DC
offset of waveform (or DC if selected)
is adjustable
to ±10 volts open circuit
and
±5
volts into matching load.
Waveform plus
offset is limited
to ±10V peak (open circuit).
Output waveforms can
be attenuated from
0 dB to 80 dB:
60 dB in 20 dB
steps plus a 20 dB vernier for continuous
variation
(20 dB vernier does not
affect
offset or
DC output).
Optional
output protection
circuit of zeners and
fuses protect
both output
and common sides
from inadvertent
connection
to
external
voltage or ac line.
DC
Offset and DC Output
DC
offset of waveform and
DC output
are selectable
and
variable thru ±10V
(±5V
into
matching
load). Waveform
plus offset
is
limited
to
±10V
peak (open
circuit). Step at-
tenuator
attenuates dc
level.
Generator Frequency TTL
Output
TTL pulse has an
approximately
50% duty
cycle
at
gener-
ator
frequency and can drive
up
to 20
TTL
loads.
Optional
TTL buffer circuit provides high
power TTL com-
patible signal
capable of driving load
impedances
as low
as
500
.
1-1