Advanced Telemetry Systems, Inc. R4500S Reference User Manual R05-11-A 2
Introduction:
The R4500S is a receiver - data logger combination with built in GPS. (An optional GPS antenna is required to use
the GPS feature)
Operationally, the R4500S works by acting as a filter to select a very narrow window in the frequency spectrum.
The position of this filter in the frequency spectrum is determined by the frequency selection (tuning). The receiver
rejects signals and noise outside the filtered window, and passes signals and noise within the window. Additionally,
the receiver translates the signal to a frequency within hearing range that can be heard from the speaker.
The R4500S can store 98304 Stationary data blocks, or 49152 Aerial data blocks or data blocks recorded in the
Manual mode. For Aerial Data, and data recorded in the Manual mode, an extra data block is needed for GPS
information. The data is stored to memory using a looping format. If the data set is maxed out, the newest data will
overwrite the oldest data block. Data blocks consist of the time stamp, frequency, transmitter data, and GPS
location if GPS is used.
The Receiver uses DSP (Digital Signal Processing) technology to achieve better sensitivity, and to help filter out
noise. The DSP digitally samples the audio signal from the R4500S. When the signal has been digitized, the DSP
processor uses internal mathematical calculations to identify signals.
The S suffix indicates the software in this receiver is programmed to detect non coded transmitters.
A non coded transmitter transmits a single pulse which is repeated at a specific pulse rate.
The R4500S can be used for fixed pulse rate transmitters, and for variable pulse rate transmitters.
For fixed pulse rate transmitters, the R4500S uses a pattern matching algorithm to detect up to 3 user entered
pulse rates. To verify a pulse rate, the pattern matching algorithm uses 4 pulses from the transmitter to verify the
pulse rate which helps separate a transmitter signal from a noise pulses. This is important to know for setting the
correct scan time for detecting pulse rates as described in sections 13.0 – 15.0.
For variable rate transmitters (temperature, depth, altitude), the R4500S uses a pattern matching algorithm to
identify transmitter pulse periods, and converts the period to the actual measurement using 2nd order regression
coefficients required to be entered for each transmitter.
Class B Device Statement: (Section 15.105 (b) of the FCC Rules)
“Note: This equipment has been tested and found to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates, uses,
and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the interference by one or more of
the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
oConnect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
oConsult the dealer or an experienced radio/TV technician for help.”
