BRIEF TECHNICAL
DESCRIPTION
INTRODUCTION
The 2040 series
low noise signal generators cover
a
wide
range of frequencies from
10 kHz to 1.35 GHz
(2040),
10 kHz to 2.7 GHz
(2041)
and 10 kHz to 5.4
GHz
(2042).
Output
levels from
-144
or
-138
dBm
to +13 dBm
(+19
dBm on 2040 with option
003 fitted) are
available.
The simplified block schematic diagram
for the instrument is shown in Fig.
4-1.
MODULATION
The carrier frequency
can be frequency, phase or amplitude modulated from
internal or
external modulation
sources. A maximum of four modulation channels
can be made available by
the use
of the internal oscillator and a second optional
internal oscillator together with two
external modulation signals
applied to the EXT MOD 1 INPUT and
EXT MOD 2 INPUT
connectors on
the front panel.
FREQUENCY
GENERATION
Four
voltage
controlled oscillators
(VCOs)
covering
the frequency range
675 to
1350 MHz are
phase
locked
to a 10 MHz oven controlled crystal oscillator
using a fractional-N
synthesizer
system. In low noise modes the noise performance
is improved using a synthesizer
system located
in the
low nose tray.
Additional frequency coverage
is
achieved
by means
of
frequency division
or multiplication. Low
frequencies are generated by a beat frequency
oscillator
(BFO) system.
DISPLAY
The display is a high definition dot
matrix liquid crystal panel
with
backlighting to
cater
for
variations
in ambient
light conditions. The display can be adjusted
for both contrast and
brightness.
CONTROL
The 2040 series
are menu driven instruments. Main menus
are
displayed
by the use of
hard keys, and
parameters are changed
by means of soft keys
which
change as the menu changes.
Internal control of the
instruments is achieved by a microprocessor which receives
data from the
various controls
and sends instructions via an internal
8-bit data bus to the signal processing
circuits.
The instruments
can also be controlled
by the built in general purpose interface bus
(GPIB). This
facility enables the instruments
to be used both as manually operated
bench mounted instruments
or as part of
a fully automated test system.
46882-074C
4-1-1
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