GENERAL INFORMATION
1-3
network before being fed to a separate combined RF output. Both sources cover the full frequency
range of 10 kHz to 2.4 GHz with an output power of between
−
137 and +24 dBm.
Each signal source can be controlled independently in frequency and level, and each has its own
amplitude, frequency, phase, FSK and pulse modulation capability. All parameters can be entered
from the front-panel keyboard and a rotary control can be used to adjust most settings.
The instrument is provided with built-in tests specifically for use with two or three combined
sources such as for amplifier and receiver intermodulation tests and receiver selectivity tests. The
sources may be locked together, offset in frequency (additionally with a harmonic or sub-harmonic
relationship) as well as level.
Microprocessor control ensures that the instrument is flexible and easy to use and allows
programming by the General Purpose Interface Bus (GPIB) or RS-232 serial bus. The GPIB is
designed to IEEE Standard 488.2 and is a means of sending commands to an instrument, via a data
bus, from a remote controller or personal computer. The instrument can therefore be used
manually or as part of a fully automated test system.
Main features
Operation
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 [
Ø
][
×
] keys or altered by
moving the control knob, set to a particular sensitivity.
Display
The display is a dot-matrix liquid-crystal panel, with backlighting. Display contrast and brightness
may be varied to accommodate differing lighting conditions and the setting saved in memory.
Frequency selection
Carrier frequency is either selected directly via the keyboard or remotely via the interfaces.
Frequency resolution is 1 Hz across the complete frequency range of 10 kHz to 2.4 GHz. A series
of carrier frequencies can be stored in non-volatile memory for recall when required.
Output
Peak RF output levels from each signal source of up to +24 dBm can be set up to 1.2 GHz
(+20 dBm up to 2.4 GHz) by direct keyboard entry with a resolution of 0.1 dB down to
−
137 dBm. The peak output level from the combiner is
−
3 dBm, 800 MHz to 2 GHz. RF
ON/OFF keys are provided to disable each individual output as well as the combined output.
A choice of level units is available to the user and provision is made for the conversion of units
(for example, dBm to
µ
V) by a simple key-press.
An electronic trip protects each independent signal source output against reverse power of up to
50 W. This prevents damage to output circuits when RF transmitter or DC power supply is
accidentally applied to an RF OUTPUT connector.
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 step attenuator.
Modulation
Comprehensive amplitude, frequency and phase modulations are available. Pulse modulation can
be applied to the carrier from an external pulse source. The instrument also produces FSK
modulated outputs. An internal modulation oscillator is provided, having a frequency range
of 0.01 Hz to 20 kHz. Sine, triangle and square waveforms are available. The oscillator is capable
of generating one or two modulation tones simultaneously in one modulation channel. A BNC
connector on the front panel offers access to the internal LP signal as well as providing an input
for external modulation signals to be combined with the internal signals. These sources can be
