Aeroflex 2944B - TECHNICAL DESCRIPTION

4-1
Chapter 4
TECHNICAL DESCRIPTION
Contents
Overview........................................................................................................................................ 4-2
Power supply .......................................................................................................................... 4-2
The display.............................................................................................................................. 4-3
Tx test mode................................................................................................................................... 4-7
Modulation sources................................................................................................................. 4-7
Audio generators.............................................................................................................. 4-7
Data generator..................................................................................................................4-8
Receiver circuits ..................................................................................................................... 4-9
Input switching ................................................................................................................ 4-9
Broad band power meter.................................................................................................. 4-9
Overload detection......................................................................................................... 4-10
Switched attenuator ....................................................................................................... 4-10
IF circuits .............................................................................................................................. 4-10
First frequency changer/mixer....................................................................................... 4-10
First local oscillator ....................................................................................................... 4-10
Second frequency changer/mixer .................................................................................. 4-10
Second local oscillator................................................................................................... 4-11
Third frequency changer/mixer ..................................................................................... 4-11
Bandwidth filters ........................................................................................................... 4-11
Demodulators........................................................................................................................ 4-11
AM demodulator............................................................................................................ 4-11
FM demodulator ............................................................................................................ 4-11
SSB demodulator (optional) .......................................................................................... 4-12
De-emphasis filter.......................................................................................................... 4-12
RF counter ............................................................................................................................4-12
Measurement ranging circuits............................................................................................... 4-12
Distortion/SINAD filter ........................................................................................................ 4-13
Oscilloscope function ...........................................................................................................4-13
Rx test mode ................................................................................................................................ 4-13
RF generator ......................................................................................................................... 4-13
Modulators............................................................................................................................ 4-14
RF amplifier.......................................................................................................................... 4-14
Audio generators................................................................................................................... 4-14
Modulation control ............................................................................................................... 4-14
Pre-emphasis filter ................................................................................................................ 4-14
AF measuring circuits...........................................................................................................4-14
Oscilloscope function ...........................................................................................................4-15
Dx test mode ................................................................................................................................ 4-15
Spectrum analyzer mode.............................................................................................................. 4-15
Look and listen function (optional) ...................................................................................... 4-15
AF test mode................................................................................................................................ 4-15
List of figures
Fig. 4-1 Block diagram of power supply module ......................................................................... 4-2
Fig. 4-2 Simplified block diagram ................................................................................................ 4-5
Fig. 4-3 AF generator detailed block diagram .............................................................................. 4-7
Fig. 4-4 Input switching and broad band power meter block diagram ......................................... 4-9