The Marconi 2955B combines all the measurement facilities required for testing mobile radio transceivers in the range up to 1000 MHz. This unit was also marketed as an IFR 2955B. The 2955B is a compact self-contained unit designed for bench or mobile use and can be considered as a combination of the following instruments: RF frequency meter, AF frequency meter, RF signal generator, AF generators (2), RF power meter, AF and DC voltmeter, Modulation meter, AF distortion meter, S/N or SINAD meter, Digital Storage Oscilloscope, Sequential tones decoder and encoder, DTMF decoder and encoder, DCS decoder and encoder, and POCSAG radio pager encoder.
The 2955B radio communications test set combines all the instruments required for transceiver testing within a single unit. Designed for bench and field, the instrument is lightweight, portable, and can be operated from all standard AC supplies or vehicle supplies.
Facilities are provided for testing all types of AM, FM, and θM mobile radio equipment, including low power hand portables and mobiles using selective calling, full duplex radio telephones, digital pocket pagers, base station, and repeater equipment.
The 2995B contains 19 instrument functions for transceiver testing: RF power meter, RF frequency meter, modulation meter, RF signal generator, dual AF signal generators, AF frequency meter, AF voltmeter, 1 kHz AF distortion meter, S/N and SINAD meter, sequential tones encoder/decoder, DTMF encoder/decoder, digitally coded squelch (DCS) encoder/decoder, POCSAG digital pager encoder, and digital oscilloscope. The instrument also functions as an ATE system, or as a set of general purpose test equipment. An option provides a sensitive, selective input for the measurement of signals as low as 1 µV.
Operation of the test set is simple. Keys configure the instrument functions to test either a transmitter and receiver together in full duplex mode, or independently for simplex or semi-duplex operation. A large, clear CRT display provides all generated and measured information relating to a test, and a direct indication of controls in use. The CRT provides the flexibility for measurements to be presented in digital form for precise unambiguous readings, from which a hard copy printout can be made.
Comprehensive testing facilities for AM, FM, and θM transceivers to 1000 MHz
Full duplex facility tests radio telephones and crossband repeaters
Optional sensitive receiver for off-air transmitter monitoring
Sequential and revertive tones, DTMF and DCS encoders/decoders
Menu driven CRT display with 26 stores for recall of standard settings
Precision digital readouts and autoranging bar charts for rapid testing
Built-in self test and operator guide
System checking of simplex transceivers in less than three seconds
Operation from any standard AC supply up to 400 Hz, or vehicle supply
Digital scope with single shot for peak modulation setting
GPIB or RS232
High stability OCXO fitted
The following specifications represent a small selection of the functions of the 2955B.
RF signal generator
Frequency range: 0.4 MHz to 1000 MHz (usable to 1060 MHz)
Frequency resolution: 50 Hz to 530 MHz, 100 Hz to 1000 MHz
Output level range in Receiver mode: -135 dBm to -15 dBm (0.04 µV to 40 mV)
Output level resolution: 0.1 dB
Harmonics: <-20 dBc up to 1.5 MHz, -25 dBc up to 250 MHz, -20 dBc up to 1000 MHz
Spurious for carrier frequencies up to 88 MHz: Better than -45 dBc up to 110 MHz, <-35 dBc above 110 MHz
Spurious for carrier frequencies up to 960 MHz: <-60 dBc
SSB phase noise at 20 kHz offset: <‑110 dBc/Hz up to 500 MHz, <‑104 dBc/Hz up to 1000 MHz
VSWR: <1.2 up to 500 MHz, <1.3 up to 1000 MHz (N-type), <2.2 up to 1000 MHz (BNC)
Internal AM CW range: 1.5 to 400 MHz, usable from 400 kHz to 500 MHz
Internal FM CW range: 0.4 to 1000 MHz, usable to 1060 MHz
Internal phase modulation CW range: 0.4 to 1000 MHz
Digital storage oscilloscope
Frequency range: DC (or 3 Hz on AC) to 50 kHz
Voltage range: 10 mV/div to 20 V/div
RF power meter
Input range: 0.05 mW to 150 W
Watts or dBm units
Frequency range: 1.5 MHz to 1000 MHz, usable to 1060 MHz
Resolution: 1% full scale
VSWR: <1.2 up to 500 MHz, <1.35 up to 1000 MHz (N-type), <2.2 up to 1000 MHz (BNC)