The Tempo SignalScout RFM151 is a high-performance RF measurement field tool
tailored for analog/digital Cable TV networks. It is designed to meet the
demanding requirements of cable television technicians performing
troubleshooting and maintenance operations anywhere in the network. The RFM151
provides all of the basic signal level easurement capabilities, and it also adds
new spectrum analysis, ingress, and digital channel RF measurement capabilities
not available in comparable products!
- Digital Channel RF Measurement Suite Includes Average Power Level Plus
- Exclusive Ingress Monitor Mode Records Ingress Violations of up to 32
User-defined Frequency and Level Windows
- Enhanced Spectrum Mode Increases Ability to Capture Lowlevel and Bursty
- AM and FM Demodulators with Speaker Helps Identify Ingress Sources
- User-changeable Battery Pack with Optional External Charger for
- CSS151 Control and Analysis Software Includes Ingress/Spectrum Analysis
Capability and Report Generation
Digital Channel Average Power
The RFM151’s stepped
integration method efficiently and accurately delivers the true average power of
QAM, QPR, QPSK, or VSB digital channels (see Figure 1). Unlike single-point
measure and calculate methods, the stepped integration technique takes into
account signal abnormalities such as un-flatness.
The Peak Analog-to-Digital
Average Power Level Difference measurement makes short work of verifying power
loading in mixed analog and digital systems. Use it to set digital modulator
levels referenced to the analog carriers.
Digital In-Channel Noise
With analog signals,
carrier-to-noise ratios are important to picture quality. A similar measurement
for digital signals is the Desired-to- Undesired Signal Ratio. This is an
in-channel (out of service) average power-to-noise measurement that includes
noise, as well as distortion signals, such as ingress and analog
system-generated CSO and CTB.
Enhanced Spectral Analysis
The RFM151’s Spectrum Mode is
an easy-to-use spectrum analysis tool that allows technicians to troubleshoot
most problems before calling for more advanced equipment. Spectrum Mode Features
- AM and FM demodulators
- Dual markers
- Noise marker
- Window Sweep™
- Max hold
- Preamp control
- Peak/average detection
Combination AM/FM demodulators with amplifier and speaker, are available both
in Meter Mode and Spectrum Mode. These detectors help the technician identify
both wanted signals, such as aural carriers, and unwanted signals, such as a
two-way radio transmission, and other ingress.
The General Purpose Spectrum Mode offers a choice of no markers, dual
frequency-amplitude markers with D readout, or noise markers (in dB/Hz) with
selectable normalized bandwidth. Other features of spectrum mode include: Window
Sweep which reduces the amount of swept display, increasing the display update
rate to show rapidly changing signals; Max Hold, to show only the highest value
of the displayed spectrum; Selectable Peak or Average detection modes, and a
preamp for making ow-level readings.
The RFM151 is the technician’s
best friend when it comes to troubleshooting ingress problems. Exclusive
circuitry minimizes forward-path signals overloading the RFM151’s input when
measuring return-path traffic. This means that low-level ingress measurements
can be taken in common path locations – such as a tap or seizure screw. Add to
this the quick scan rate of Window Sweep, max hold, peak detect, demodulation,
field strength, and preamp controls and the RFM151 is able to measure
return-path bursty signals and low-level ingress down to –65 dBmV (–5dB?V) to
help locate the source (see Figure 2).
Another unique RFM151 feature is the
Ingress Monitor Mode which allows up to 32 frequency windows to be defined
within the displayed spectrum, each with its own level threshold (see Figure 3).
When a signal violates the threshold, the instrument either stops and shows the
display, stores the violation in memory, or continues. Violations can be stored
as frequency/amplitude/time data, or complete spectrum displays with time
stamps. Sweep delays can be set from 2 to 60 minutes in one-minute intervals
allowing unattended monitoring.
The SignalScout provides five different
level displays: Single Channel, 5-channel, Pilots, All Channels, and Meter.
These display modes can show either analog or digital channel
The 5-channel display mode provides both a numerical reading and
a bargraph display. This is great for doing system-at-a-glance measurements and
looking at tilt. The Pilots display mode shows both bargraph and numeric
displays of any two frequencies used for setting the AGC in the
The RFM151 also performs the following
measurements: Carrier-to-Noise, Hum, FM Deviation, and Field Strength.
Carrier-to-Noise can be configured for either In-Service (using the guard band)
or Out-of-Service (with a user-settable frequency offset). Both measurements are
normalized to the proper bandwidth for the system (4MHz for NTSC and 5MHz for
The Relative Field Strength mode allows the user to select a frequency
between 5 and 1080MHz and use an optional antenna to locate the signal of
interest. Field Strength Mode is useful for finding leaks in the cable plant and
locating the sources (see Figure 4).
The RFM151 works on any world
television standard and all common transmission standards. It automatically
measures the average power of a NICAM sound carrier. Just enter the correct
frequency into the second aural carrier slot and the RFM151 does the rest.
Customized Settings – Time-Saving Measurement
The RFM151 and CSS151 Software form a powerful tool
tailored to an individual cable system. By creating automatic test sequences
using the CSS151 software, test time and errors are reduced. Tests can be setup
to run at fixed time intervals using the interval timer in the RFM151, or under
technician control. These sequences can be used for the FCC required tests
including the 24-Hour test, or just for routine maintenance.
Data in the worksheet can be printed
directly, or processed into concise reports for hard copy files. Reports include
a Status Report that shows how well the system is performing with regard to
level differences between adjacent channels and minimum and maximum level
differences. Another report shows the visual carrier level and visual-to-aural
carrier difference over four six-hour time periods for monitoring system
performance over time and temperature. Both reports can be printed with up to
six lines of header text for displaying additional information.
Input Impedance – 75 W (nominal).
Type – Male type F with precision female-to-female F
Range – 5 to 1080 MHz.
Accuracy – ±5 kHz or
±10–5 of tuned frequency,
which ever is greater.
ANALOG AND DIGITAL LEVEL MEASUREMENTS
Sensitivity – –35
to 60 dBmV (+25 to +120 dB?V).
Repeatability – ±0.5 dB.
DIGITAL TO ANALOG CARRIER DIFFERENCE
Select Mode – Automatic or user selectable.
Accuracy – ±2 dB.
IN BAND CARRIER TO NOISE
Measurement Location – User
Accuracy – ±2 dB.
Range – Up to 51 dB with carrier amplitude
GUARD BAND CARRIER TO NOISE
Measurement Location – Guard
(»1.25 MHz below the visual carrier).
Accuracy – ±2 dB.
Range – Up
to 47 dB with carrier amplitude >0 dBmV.
DESIRED TO UNDESIRED
Measurement Location – In channel
(Out of Service).
Accuracy – ±2%.
Fundamental Frequency – 50/60 Hz,
Range – 0 to 5%.
Accuracy – ±1%.
Accuracy – ±10% of peak deviation
±2kHz whichever is greater.
General Purpose (Dual/Noise/No
Demod (AM, FM detectors, speaker).
(up to 32
user-defined thresholds within a displayed spectrum).
Frequency Range: 5 to 1080 MHz.
Span/Division: 4 MHz, 2 MHz, 1 MHz, 400
Span 1 MHz: 300 kHz.
Sensitivity: –60 dBmV (–65 dBmV typical).
Free Dynamic Range:
20 to 1080 MHz: –50 dBc.
5 to 20 MHz: £–40
Detection Mode: Peak or Average.
Vertical Scales: 2, 5, 10, 15
Other Controls: Preamp, Max Hold.
Operating: 0 to +50° C
(+32 to +122° F).
Non-operating: –20 to +60° C
(–4 to +140°F).
Operating: 5 to 95% from 0 to +50° C.
Operating: Up to
15,000 ft. (4,550 m).
Non-operating: Up to 40,000 ft. (12,192 m).
DC Input Range – +10 to +15 VDC.
Requirement – 10 W maximum.
Battery Type – User replaceable.
– 2.75 Hr.