are portable and lightweight synthesized
signal generators covering the
frequency range 9 kHz to 1.2 GHz (2023
, and 9 kHz to 2.4 GHz
,. A dot matrix display
with a comprehensive set of utility menus allow flexibility
of operation and ease of use. The RF
output can be amplitude, frequency, phase or pulse
modulated. An internal programmable AF
source is capable of generating simultaneous two-tone
All parameters can be entered from a front panel keyboard
and a rotary control can be used to
adjust most settings. Microprocessor control ensures that
the instruments are flexible and easy to
use and allows programming by either the General Purpose
Bus (GPIB) or by RS-232.
The GPIB is designed to IEEE Standard 488.2. The interfaces
allow remote control of all
functions except the supply switch, and allow the
instruments to be used either manually or as part
of a fully automated test system.
Selection of parameters on the screen may involve one or
more of the numeric, hard or menu
selection keys or the rotary control knob. Parameters may be
set to specific values by numeric key
entry, while values may be varied in steps of any size using
the DOWN/UP keys or altered by
moving the control knob, set to a particular sensitivity.
The display is a dot matrix liquid crystal panel, with
backlighting. Display contrast may be varied
to accommodate differing lighting conditions and the setting
saved in memory. A graphical
display test is available to the user.
Carrier frequency is either selected directly via the
keyboard or remotely via the interfaces.
Frequency resolution is 1 Hz across the band. A series of
carrier frequencies can be stored in nonvolatile
memory for recall when required.
RF output up to +13 dBm can be set by direct keyboard entry
with a resolution of 0.1 dB over the
entire range. For instruments fitted with the high power
option, RF output is increased to
+25 dBm. A carrier ON/OFF key is provided to completely
disable the output.
A choice of level units is available to the user and
provision is made for the conversion of units
(for example, dBm to μV) by a simple keypress.
An electronic trip protects the Generator
reverse power of up to 50 W. This prevents
damage to output circuits when RF or DC power is
accidentally applied to the RF OUTPUT
To facilitate testing of receiver squelch systems, an
attenuator hold function allows control of the
RF output without introducing RF level drop-outs from the
The RF output level can be offset by up to ±5.0 dB to
compensate for cable or switching losses, or
standardize a group of instruments.
Maximum RF output level can be set so as to protect
sensitive devices connected to the RF
With an SSB phase noise performance of typically -121 dBc/Hz
at 20 kHz offset from a 1 GHz
carrier, these instruments can be used for both in-channel
and adjacent channel receiver
measurements. Harmonically related signals and non-harmonics
are typically better than -25 dBc
and -60 dBc respectively.
This instrument has a recommended two year calibration
interval after which it should be returned
for recalibration (for addresses refer to 'Addresses'
section at end of manual).
Comprehensive amplitude, frequency and phase modulations are
available. Pulse modulation can
be applied to the carrier from an external pulse source. The
instrument also accepts one or two
logic level inputs to produce a 2-level or 4-level FSK
modulated output. An internal modulation
is provided, having a frequency range of 0.01 Hz
to 20 kHz. The Oscillator
is capable of
generating one or two modulation tones simultaneously in one
modulation channel. An
independent BNC input on the front panel allows external
modulation signals to be combined with
the internal signal(s). These sources can be combined to
give a number of modulation modes.
The pulse modulation can be used in combination with the
other forms of modulation.
The frequency modulation range provides a 1 dB bandwidth of
typically 100 kHz and provides
FM deviation up to a maximum of 100 kHz. AC or DC coupled FM
can be selected. Phase
modulation is also available with a 9 kHz bandwidth up to a
maximum of 10 radians.
Amplitude modulation with a 1 dB bandwidth of typically 30
kHz and with modulation depths of
up to 99.9% is available with a resolution of 0.1%. Pulse
modulation is available as standard with
typical rise and fall times of less than 10 μs and 40 dB
The external input voltage required for 100% modulation is 1
V RMS or, optionally, 1 V peak. To
accommodate other signal levels, Automatic Level Control
(ALC) can be selected which provides
correctly calibrated modulation for inputs between 0.75 and
1.25 V RMS.
A MOD ON/OFF key simplifies the testing of signal to noise
An optional fast pulse modulator improves the rise/fall
times to typically 10 ns.
All major parameters can be incremented or decremented in
step sizes entered via keyboard entry
or remotely. If no step size is entered for a parameter, the
steps are preset to 1 kHz for carrier
frequency, 1 kHz for modulation Oscillator
, 1 kHz for FM
deviation, 0.1% for AM depth, 0.01 rad
for ΦM and 1 dB for output level.
In addition, the rotary control knob can be used to vary the
parameter with the sensitivity of the
knob being changed by means of the ×10 and ÷10 keys.
The sweep capability of the instrument allows comprehensive
testing of systems. Sweeps may be
logarithmic or linear. Four parameters are used to specify
sweep; start, stop, step size and time per
step and a percentage increment in the case of logarithmic
sweep, all of which may be specified by
the user. The sweep can be paused at any time. During the
sweep the RF level can be altered
using the rotary control. Sweep triggering can be single
shot or continuous and can be initiated
directly or on the detection of a trigger. The triggering
signal may either be programmed or from a
TTL signal applied to the rear panel TRIGGER input.
The instrument provides both non-volatile and volatile
memory for storing instrument settings.
The non-volatile memory provides 100 instrument settings and
100 settings of carrier frequency
only. The volatile memory (RAM) also provides 100 instrument
settings. Any one of the nonvolatile
instrument settings can be selected as the power-up setting
for the instrument.
The stored settings in one instrument can be easily
transferred (without the use of a controller) to
another instrument using the RS-232 Interface
, or to several
other instruments using the GPIB
facility allows sequences of stored instrument
settings to be defined. The incrementing
facilities can then be used to cycle through the settings in
manually operated test systems or be
operated via an external trigger.
To prevent accidental change of the contents of the stored
settings, individual memories or ranges
of memories can be write-protected.
A GPIB Interface
is fitted so that all functions are
controllable via the Interface
bus which is
designed to the IEEE Standard 488.2. The instrument can
function both as talker and listener.
The instrument also has an RS-232 Interface
which uses the
common GPIB command set. The
interfaces enable the instrument to be remotely controlled
as well as being used to transfer settings
(cloning) from one instrument to another.
All alignment data is digitally derived. Realignment can be
undertaken, without removing covers,
by protected front panel functions or via the GPIB Interface