Wireless
2948
Low Phase Noise
Communications Service Monitor
All the benefits of the 2945A but with a low phase noise signal generator,
for the more critical receiver testing
•
•
•
•
•
•
•
Low phase noise signal generator
High stability reference oscillator (OCXO)
as standard
Accurate power measurement to 150 W
Transient and harmonic analysis
Fast response high resolution bar charts
for peaking and nulling
Tracking generator with full offset track-
ing
Full span spectrum analyzer with ‘live’
look and listen
Field Operation
At under 12 kg the 2948 lightens the load to remote sites. The shape
of the 2948 is ideal for carrying; the side handle ensures that the
instrument is clear of the stairs when ascending buildings and the
2948’s depth is suitable for the instrument to be operated comfort-
ably when it is placed on the floor.
An optional bail arm handle is also available. This option allows a
stowage cover to be fitted over the front panel for storage of adapters
and further protection to the instrument’s front panel. Full opera-
tion is possible from the protective ‘ever-ready’ case so that your
investment is protected from transit damage.
Stored settings may be recalled from internal memory or from a
memory card allowing fast and straightforward setting up.
Fast Full Performance Spectrum Analyzer - provided as stan-
dard
The 2948 Communications Service Monitor is
the lightest, most rugged service monitor avail-
able with low phase-noise signal generation.
For field work, the 2948 provides an excellent
combination of instruments for all types of
maintenance work. In the workshop it provides
all of the performance you would expect for
exacting measurements.
Low Phase-Noise Signal Generator
The 2948 differs from its 2945A cousin by provid-
ing a low phase-noise signal generator as standard.
This enhanced capability allows accurate meas-
urement of the noise characteristics of all FM
receivers and is especially beneficial when making
accurate measurement of narrow band receivers.
The performance of the 2948 enables signal-to-
noise measurements of better than 46 dB to be
made on receivers with 12.5 kHz channel spacing.
The spectrum analyzer provides spans from 100 Hz per division to
100 MHz per division and also has a fully adjustable reference level.
Speed is comparable with analog analyzers, allowing real time adjust-
ments over the displayed dynamic range. With the tracking genera-
tor provided as standard, duplexers and filters can be aligned quick-
ly and easily. An offset facility provides testing of equipment with fre-
For the very latest specifications visit
www.aeroflex.com
quency translation. Channel stepping can be performed by defining
an increment and then using the FREQ
keys. This is particular-
ly useful when testing multi-channel systems.
Live Look and Listen
This feature puts the 2948 above all of its peers with the ability to
examine signals on the screen and demodulate them simultaneously.
Intermittent interference can be isolated quickly and the signals then
easily identified. The trace can be saved to memory card along with
the time and date, providing factual evidence that can be recalled
later. This feature is particularly useful when looking for rogue trans-
missions, especially on busy base station sites.
From 2 µV to 150 Watts
The 2948 measures the power of low level signals such as those
encountered when monitoring off-air signals or those found when
probing a circuit. 150 Watts measurement is provided without the
need for external attenuators, so the high power of base stations can
be measured directly. Measurement accuracy of better than 10% is
guaranteed all the way down to 5 mW on the N-Type connector, allow-
ing cellular radios to be qualified at low power levels.
Accurate RF Signals
The signal generator provides coverage from 400 kHz to 1.05 GHz
with +5 dBm output (+7 dBm overrange) and fast switching speed.
Level accuracy is ±2 dB at all levels above -127 dBm.
Duplex - provided as standard
Full duplex operation is provided by the 2948. This allows testing of
duplex radios as well as simultaneous testing of repeater transmit and
receive paths. There are no restrictions to the duplex offset.
Cellular and Trunking - built in
AMPS, TACS and NMT analog cellular standards are available inter-
nally, with all country variants provided in each package. Trunking for
MPT 1327/1343 and variants of them is also available.
A new trunking capability has been added with the introduction of
EDACS™ Radio and Repeater test capability.
Remote control of the inbuilt tests is provided, so that measurements
can be started and results logged automatically.
Remote Control - RS-232 or GPIB
Remote control is provided, with an RS-232 interface as standard. An
IEEE-488.2 interface (option 5) can be fitted where other instru-
ments are required to operate in a system with the 2948.
Printing Made Easy
With the parallel printer port interface, screen dumps, automatic test
results or previously stored results may be sent to most parallel print-
ers. These facilities are available as standard using the serial
RS-232 interface.
A screen capture facility is available so any screen displayed on the
2948 can be saved direct to a PC via the serial port as a bit map file.
Autorun - internal control
With the Analog Systems Card fitted, automatic testing without an
external controller is possible. Custom tests may be written and run
by the operator. Four programmable relay contacts are provided with
the optional parallel printer interface. This allows remote control of
radios or test fixtures from built-in automatic tests.
Custom Programs
Users may program the instrument to suit their own specific needs.
This is possible either by configuring any of the 4 built-in programs
or by using the MI-BASIC interpreter to produce a customised test
program that can be executed internally, without an external con-
troller.
Memory Card - with real time clock
The memory card drive meets the PCMCIA standard format for PC
cards. The 2948 provides a DOS based filing system that allows trans-
fer of information to a PC fitted with a memory card slot.
Test setups, test results, screen dumps, spectrum analyzer co-ordi-
nates and test sequences can all be stored on the memory card, allow-
ing information to be easily stored and retrieved when required.
Reliability
The 2948 features high integration and a chassis designed to max-
imise mechanical protection.
Audio Analysis
A comprehensive range of filters are provided as standard, including
band pass, low pass and high pass. Optional filters are available for
psophometric weighting of audio signals and demodulation of signals
in a simulated radio channel bandwidth.
The direct measurement of CTCSS is possible with the 300 Hz LP
filter, even with speech present.
Network Simulation
The 2948 simulates the signalling protocol that the radio would see
from the real network. This allows calls to be set up and handled
enabling receiver and transmitter parametric measurements to be
made.
T comprehensive audio generators are provided as standard for
wo
internal modulation or audio sources for transmitter stimulus.
External DC coupled FM is provided.
Comprehensive Oscilloscope
Analysis of audio signals, whether from the demodulated signal or the
audio input direct can be viewed for further inspection. The oscillo-
scope can either be combined with the measurement screen in the
Tx, Rx or AF test modes or ‘zoomed’ to a full screen display.
Different levels of persistence can be selected to allow short or long
term effects to be captured.
SPECIFICATION
RF SIGNAL GENERATOR
FREQUENCY
Frequency Range
400 kHz to 1.05 GHz
Resolution
10 Hz
Indication
10 digit display
Setting
Keyboard entry, delta increment/decrement function and rotary control
Accuracy
As frequency standard
Transient Analysis
The ability to capture transients on the rising or falling edge of a
waveform provides a valuable tool for fault finding radios and radio
systems. The user has full control of the trigger level and input atten-
uation as well as the timebase and five fixed trigger points, making
this feature simple and flexible to operate.
Harmonic Analysis
An automatic harmonic analysis function is included in the 2948.
This complements the fast spectrum analyzer and allows a rapid
check that the transmitter under test is not producing any excessive
harmonics.
Tones Generation and Decoding
The tones menus include full remote control so that radio workshops
can further automate their tasks and better control the tones from the
top level screens.
POCSAG Decode - built in option
Off-air decoding of POCSAG signals is provided as an option.
This allows tone, numeric and alphanumeric messages to be dis-
played. Signals with bit rates of up to 4800 bits/s can be automatical-
ly decoded making the 2948 an ideal surveillance tool. The 2948 can
be set to detect all messages, a user selectable RIC (just like a pager),
or a fixed message string.
OUTPUT LEVEL
Output Level Range
Rx Test:
N-Type socket: -141 dBm to -21 dBm
BNC socket: -115 dBm to +5 dBm (overrange to +7 dBm)
Resolution
0.1 dB
Indication
4 digits plus sign (dBm, dBµV, µV, mV PD/EMF).
Accuracy
±2 dB for level above -127 dBm on N-Type socket up to 1 GHz
Reverse Power Protection
N-Type: 50 W 10 minutes, normal operation. 150 W for 1 minute at
20 °C.
Overload indicated by audible and visual warning.
BNC: 5 W Overload indicated by audible and visual warning.
Output Impedance
Nominally 50
Ω
VSWR
N-Type
Better than 1.2:1 up to 500 MHz
Better than 1.35:1 up to 1.05 GHz
BNC
Better than 2.2:1 up to 1.05 GHz
For the very latest specifications visit
www.aeroflex.com
SPECTRAL PURITY
Residual FM
Less than 6 Hz RMS (0.3 to 3.4 kHz) up to 500 MHz
Less than 12 Hz RMS (0.3 to 3.4 kHz) up to 1.05 GHz
Harmonics
-25 dBc
Spurious Signals
Better than -50 dBc
SSB Phase Noise (20 kHz offset)
Better than -112 dBc/Hz up to 500 MHz
Better than -108 dBc/Hz up to 1 GHz
RF Carrier Leakage
Less than 0.5 µV PD generated in a 50
Ω
load by a 2 turn loop
25 mm from the case. Output level less than -40 dBm into a sealed
50
Ω
load.
AMPLITUDE MODULATION - INTERNAL
Frequency Range
400 kHz to 1.05 GHz
AM Depth Range
0 to 99%
Resolution
1%
Indication
2 digits
Setting
Keyboard entry, delta increment / decrement function and rotary con-
trol
Accuracy
For carrier frequencies from 1.5 MHz to 400 MHz
±5% at 50% for modulation frequency of 1 kHz.
±7% ± 1 digit for modulation frequency of 1 kHz.
±15% ±1 digit for modulation frequencies from 50 Hz to 15 kHz.
Distortion
Less than 2% at 1 kHz for 30% AM, CCITT weighted
Modulation Frequency
20 Hz to 20 kHz
AMPLITUDE MODULATION - EXTERNAL
Input Impedance
Nominally 10 k
Ω
in parallel with 40 pF
Frequency Range
As internal AM
Modulation Frequency Range
As internal AM
Sensitivity
1 V RMS for 100% AM
FREQUENCY MODULATION - INTERNAL
Frequency Range
400 kHz to 1.05 GHz
Maximum Deviation
75 kHz
Indication
3 digits
Setting
Keyboard entry, delta increment/decrement function and rotary control
Accuracy (1)
±7% at 1 kHz modulating frequency
±10% at modulating frequencies from 50 Hz to 15 kHz
Distortion
Less than 1% at 1 kHz for deviation of 5 kHz, CCITT weighted
Modulation Frequency Range
20 Hz to 25 kHz
Resolution
25 Hz
Pre-emphasis
750 µs selectable
FREQUENCY MODULATION - EXTERNAL
Input Impedance
Nominally 10 k
Ω
in parallel with 40 pF
Frequency Range
As internal FM
Modulation Frequency Range
DC to 100 kHz
Pre-emphasis
750 µs selectable
Sensitivity
1 VRMS for 0 to 75 kHz deviation
MICROPHONE INPUT
Input Level
2 mV to 200 mV (AGC levelled)
Input Impedance
Nominally 150
Ω
Press To Talk (PTT)
When using the optional microphone in Tx Test mode, the PTT will
switch instrument to Rx Test.
AUDIO VOLTMETER
Input Impedance
Nominally 1 M
Ω
in parallel with 40 pF
Frequency Range
DC and 50 Hz to 50 kHz
AC only 50 Hz to 50 kHz
Polarized DC (below 1 Hz)
Maximum input voltage
30 VRMS, 50 Vdc
Level Ranges
0 - 100 mV to 0 - 100 V RMS in a 1, 3, 10 sequence
Digital readout also in mW (user selectable)
Resolution
1 mV or 1% of reading
Indication
3 digits and bar-chart
Accuracy AC
±3% ±3 mV ± resolution up to 30 V RMS
Accuracy DC
±1% +50 mV up to 40 V
Resolution
0.1% distortion
Indication
3 digits and bar-charts
Accuracy
±1 dB of reading ± 0.5% distortion
Sensitivity
50 mV (100 mV for 1% distortion) reading suppressed if audio voltage
is less than 5 mV
AUDIO S/N METER
Range
0 to 30 dB and 0 to 100 dB
Resolution
0.1 dB
Indication
3 digits and bar-chart
Accuracy
±1 dB
Sensitivity
50 mV (100 mV for 40 dB S/N) reading suppressed if audio voltage is
less than 5 mV
AUDIO FREQUENCY METER
Frequency Range
20 Hz to 50 kHz
Resolution
0.1 Hz, less than 10 kHz
1 Hz, at 10 kHz and above
Indication
5 digits
Accuracy
As frequency standard ± 1 digit ± resolution
Sensitivity
50 mV
AUDIO OSCILLOSCOPE
Operating Modes
Single or repetitive sweep
Frequency Range
DC to 50 kHz, 3 Hz to 50 kHz AC coupled
Voltage Range
10 mV to 20 V per division in a 1, 2, 5 sequence
Voltage Accuracy
±5% of full scale
FM Ranges
±75, 30, 15, 6, 3 and 1.5 kHz deviation full scale, ±10% accuracy
AM Ranges
20, 10 and 5% per division, ±10% accuracy
Timebase
50
µ
s/div to 5 s/div in a 1, 2, 5 sequence
Graticule
10 Horizontal by 6 Vertical divisions
Special features
Built in antialiasing circuitry and variable decode trigger level
AUDIO SINAD METER
Frequency
1 kHz
Range
0 to 18 dB and 0 to 50 dB
Resolution
0.1 dB
Indication
3 digits and bar-charts
Accuracy
± 1 dB
Sensitivity
50 mV (100 mV for 40 dB SINAD) reading suppressed if audio voltage
is less than 5 mV
AUDIO DISTORTION METER
Frequency
1 kHz
Range
0 to 10% and 0 to 30%
AUDIO BAR CHARTS
Bar-chart Displays
AF Voltage, SINAD, Distortion, S/N
For the very latest specifications visit
www.aeroflex.com
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
