Custom Products for the Repeater Builder
Microminiature
Audio Processing Module
For Two-Way Radio
Applications
Model AP-50
Click Here for instructions in .PDF format:
Version "A"
Version "C"
Ordering instructions below.
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The AP-50 is the most versatile 2-way radio audio processor module available.
This product is mostly surface mount to minimize size and allow an
installation concept similar to the Com-Spec TS-64. It can
be used stand alone in existing repeater/link applications, or, available
as an option for use with modern repeater controllers like the SCOM 7330.
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Actual Size ~30x45mm
Special Limited Time Price - $60
Description:
The Repeater Builder AP-50 Audio Filter/Limiter Audio Processing Module
replaces the "Blob" or stock
clipper/filter sections in Two-Way FM radio transmitters. While this
circuitry was originally designed for use in a repeater, it can also be used
to feed other transmitters' modulator directly from a discriminator source
like in cross band repeaters,
voting systems, or links. The module has 3 controls for setting the
amount of clipping (or processing), the cut-off frequency of the low pass
filter (or bandwidth), and the amount of deviation. The module has
solder pad jumpers to 'program' the type of audio feeding the board, and
the type of audio that will feed the modulator. The jumpers allow
either pre-emphasized or normal (flat) audio to feed the clipper/filter, and allow
either flat or pre-emphasized audio output to feed the modulator; which
accommodates either PM or FM modulators to be properly driven. The
low pass filter has an elliptic response created by a switched capacitor
filter to provide 'brick-wall' filtering. The cut-off frequency is
set by adjusting a potentiometer. The approximate
cut-off range is between 2500 and 5500 Hz. to accommodate anything from
15 kHz. spaced 2 meter pairs to 25 kHz. spaced UHF repeater, link, or auxiliary
allocations. Unlike other modules available at the time of this writing,
this unit is totally adjustable. This allows you to set the bandwidth
for the situation, instead of settling for a mediocre compromise of like
say 3000 Hz. This is especially true where you are conveying wide
band audio in satellite or remote receiver applications so the voter sees
enough noise bandwidth to vote properly. Frequencies between 3000
and 5500 Hz. are very important in voting, just make sure you are linking back
on a wide band channel.
The module is capacitively coupled with 10 uF non-polarized capacitors
throughout to ensure wide frequency response and no cut off of low frequency
signals like PL/DPL signals that may exist with the repeated audio.
The module has a dedicated PL, DPL, or CTCSS, CDCSS input. This
input is mixed in after the clipper/filter section of the processor to
insure proper low distortion modulation of "PL" tones, and helps eliminate
"talk-off". This input
is DC coupled and can be driven directly by modern CTCSS/PL or CDCSS/DPL
modules. Since the output coupling capacitor is very large, 10 uF,
it allows DPL to be passed without distortion by giving the module a 'near
dc' low frequency response. The module can be driven directly with
the familiar Com-Spec SS/TS-32, SS/TS-64, TS-64DS or similar tone modules.
Here's an Evaluation Article of
the AP-50 by Bob Meister WA1MIK.
Concept:
The module is used to process audio feeding a Frequency Modulated (FM)
or Phase Modulated (PM) transmitter. Many times the stock audio processing
(clipper/filter) portion of a transmitter can limit the audio bandwidth
of the system. By using this module, a setable frequency bandwidth
is obtained in addition to amplitude limiting. A custom integrated
circuit is used to do most of the processing, including amplitude limiting
and set-able frequency filtering. The custom chip is provided voltage
from an on-board regulator to ensure stable operation. A second integrated
circuit op-amp is used to buffer the output of the custom chip to drive
low impedance loads (modulators) directly. Using this module will insure
the best transmitted audio within the bandwidth limitations of your particular
service. It will also prevent your transmitter from splattering or
making adjacent channel interference as a result of using unprocessed audio.
In commercial applications, the use of this product *may* void the the
radios FCC Type Acceptance, so be sure of your intentions.
Specifications:
| Power Source |
+12 to +16 VDC, must be constant, not switched. |
| Frequency Response |
Less than 50 Hz. to 90% of Fc - +/- .25 dB typical on main input.
Near DC to 100 kHz +/- .25 dB typical on PL/DPL input. |
| LPF Cutoff Frequency |
2500 to 5500 Hz. |
| Minimum Audio Input Level |
200 mV P-P |
| Input Impedance |
Approximately 10 K Ohms. |
| Output Impedance |
Approximately 100 Ohms. |
| Maximum Audio Output Level |
0 to 8 Volts P-P, but depends on supply voltage. |
| LPF Rolloff |
-30 dB at 144% of Fc (see chart below) |
Features:
The latest and
smallest adjustable (programmable) Audio Processor Module for use in FM/PM
transmitters and repeater controllers.
Brick Wall Filtering.
Low Noise.
Wide Frequency
Response, great for Flat Audio Repeaters, and Satellite Link-Back (voter)
applications.
Very Low Distortion
and Group Delay
Low Power Consumption,
<20 mA. typical.
Adjustable Clip
Level, LP Filter Cut-Off Frequency, and Deviation Level.
Small Size (approx.
1.2 x 1.8 x .3 inches)
Operating temperature
range is -20°C to +60°C
Simple to hook-up
and set-up.
Module is reverse
polarity protected.
Mating
power/signal connector can be plugged on backwards without incident.
90 day Limited
Warranty. Repair available for units out of, or not covered, under
warranty (factory determined).
Mounts with double
sided foam tape (not included)
Hookup is made
from miniature 5 pin male .100 header pins.
Mating
female socket and pins are supplied so you can make your own wiring harness.
Can be used to
drive a link transmitter from a computer (or other flat) source like a
sound card.
Detailed
Set-Up and Instructions included.
Email
Scott Zimmerman for ordering information and/or quantity pricing of this exciting product.
Product of Repeater Builder, all rights reserved.
Design owned by Kevin Custer.
Specifications may change without notice.
Copyright 2005, Repeater Builder.
Images property of Repeater Builder.
Logo Design by Elisha Zimmerman KB9WCX
HTML May 8 2005, W3KKC All Rights Reserved!