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5-1
Chapter 5
BRIEF TECHNICAL DESCRIPTION
Introduction
The 2050T series signal generators cover a wide range of frequencies from 10 kHz to 1.35 GHz
(2050T), 10 kHz to 2.7 GHz (2051T) and 10 kHz to 5.4 GHz (2052T). Output levels from -144 or
-138 dBm to +13 dBm 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.
In vector modulation IQ modulation is provided from 10 MHz up to 2.7 GHz by frequency
conversion of 1 of 4 IFs to the required output frequency. In digital modulation a vector
modulated RF carrier is generated from data inputs.
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. 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 2050T 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.