JPS PTG-10 User manual

Installation and Operation Manual
PTG-10
Pilot Tone Generator
Designed and Manufactured by:
JPS Interoperability Solutions
5800 Departure Drive
Raleigh, NC 27616
919-790-1011
Email: [email protected] / [email protected]
JPS P/N 5970-900200 Revision 4.0 May 19, 2016

PTG-10 Operations Manual
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CAUTION
Changes or modifications to this equipment not expressly approved by JPS
Interoperability Solutions could void the user’s authority to operate this
equipment.
NOTICE
JPS Interoperability Solutions reserves the right to make changes to the
equipment and specifications without prior notice.
PROPRIETARY STATEMENT
The information contained in this manual is the property of JPS Interoperability
Solutions and is intended for the purchaser’s use only. It may not be reproduced
without the expressed written consent of JPS Interoperability Solutions.
© 2016 JPS Interoperability Solutions, Inc.
JPS Interoperability Solutions, Inc.
5800 Departure Drive
Raleigh, NC 27616
Phone: [phone]
Fax: [phone]
Email: [email protected] / [email protected]

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Table of Contents
1GENERAL INFORMATION............................................................................................................................1-1
1.1 SCOPE...................................................................................................................................................1-1
1.2 DESCRIPTION ........................................................................................................................................1-1
1.2.1 General............................................................................................................................................1-1
1.2.2 Circuitry and Block Diagrams ........................................................................................................1-2
1.2.3 Mechanical Assembly......................................................................................................................1-2
1.2.4 Function and Operation..................................................................................................................1-2
1.2.5 Power Supply ..................................................................................................................................1-2
1.2.6 Limitations ......................................................................................................................................1-2
2INSTALLATION..............................................................................................................................................2-1
2.1 GENERAL..............................................................................................................................................2-1
2.2 UNPACKING AND INSPECTION...............................................................................................................2-1
2.3 RESHIPMENT OF EQUIPMENT ................................................................................................................2-1
2.4 INSTALLATION OVERVIEW....................................................................................................................2-2
2.5 INSTALLATION CONSIDERATIONS .........................................................................................................2-2
2.6 POWER REQUIREMENTS........................................................................................................................2-2
2.7 CONFIGURING THE PTG-10 ..................................................................................................................2-3
2.7.1 Jumper Settings...............................................................................................................................2-3
2.7.2 Potentiometer Adjustments..............................................................................................................2-3
2.8 INTERCONNECT INFORMATION .............................................................................................................2-4
2.8.1 Input and Output Connections Plus Power and Ground.................................................................2-4
2.9 SETTING LEVELS...................................................................................................................................2-4
3OPERATION...................................................................................................................................................3-1
3.1 GENERAL..............................................................................................................................................3-1
3.2 OPERATIONAL INDICATORS ..................................................................................................................3-1
3.2.1 Power Indicator ..............................................................................................................................3-1
3.2.2 Tone Indicator.................................................................................................................................3-1
3.3 OPERATION...........................................................................................................................................3-1
4THEORY OF OPERATION.............................................................................................................................4-1
4.1 GENERAL..............................................................................................................................................4-1
4.2 TONE CIRCUIT ......................................................................................................................................4-1
4.3 POWER SUPPLY.....................................................................................................................................4-1
5MAINTENANCE AND REPAIR......................................................................................................................5-1
5.1 GENERAL..............................................................................................................................................5-1
5.2 PREVENTIVE MAINTENANCE.................................................................................................................5-1
5.3 REPAIR OR REPLACEMENT....................................................................................................................5-1
5.3.1 General Precautions and Notes ......................................................................................................5-1
6INDEX.............................................................................................................................................................6-1

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List of Figures
FIGURE 2-1 –OUTLINE DIMENSIONS........................................................................................................................2-5
FIGURE 2-2 –LOCATIONS OF INDICATORS AND ADJUSTMENTS................................................................................2-6
FIGURE 5-1 –CIRCUIT DIAGRAM 1...........................................................................................................................5-2
FIGURE 5-2 –CIRCUIT DIAGRAM 2...........................................................................................................................5-3
FIGURE 5-3 –WIRING DIAGRAM 1...........................................................................................................................5-4
FIGURE 5-4 –BLOCK DIAGRAM 1 ............................................................................................................................5-5
List of Tables
TABLE 1-1 SPECIFICATIONS .........................................................................................................................1-3
TABLE 1-2 EQUIPMENT AND ACCESSORIES SUPPLIED..........................................................................1-3
TABLE 2-1 JP1-INPUT/OUTPUT CONNECTOR .....................................................................................................2-4

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1-1
1 General Information
1.1 Scope
This instruction manual provides the information necessary to install, operate, and maintain the
PTG-10 Pilot Tone Generator.
1.2 Description
1.2.1 General
In an LMR voting system, receivers are strategically placed throughout a geographic area (at
voting sites) to fill in dead spots where portable radios cannot normally be heard by other
portables, by the repeater, or by the dispatcher. The audio from each receiver is linked to the
voter, which continuously compares the signals from all receivers and passes through the best
quality signal to the dispatcher or to the local repeater. In this way, any portable in the voting
area can be heard by the dispatcher, or by any other portable through the local repeater. In this
system, it is necessary to transfer a receiver’s COR or COS (Carrier Operated Relay or Carrier
Operated Squelch) signal to the voter from a remote receiver site. COR is an indication that the
receiver has broken squelch; the voter needs this information to know which receiver site or sites
are currently unsquelched and therefore receiving a valid input signal.
The PTG-10 Pilot Tone Generator Module produces a controlled pilot tone that transfers the
COR signal from a remote receiver site to a voter. The PTG-10 transfers the COR signal over
the same path as the receive audio, eliminating the cost of a second communications path for the
COR signal. Audio output (an AC signal) exits a receiver through one pair of wires and the COR
(a DC logic signal) exits the receiver on another wire making it impossible to carry both the audio
and the COR on the same audio pair. The PTG-10 converts the COR signal to a tone which is
mixed with the audio from the receiver, removing the need for a COR line. The PTG-10 works
by injecting a pilot tone on the audio line whenever the associated receiver is squelched, and
removes the tone whenever the receiver is unsquelched. When the receiver used in the voting
application detects carrier (receives a signal), it unsquelches and issues a COR signal to the PTG-
10. When the PTG-10 receives a COR signal the tone is removed from the audio link and the
receiver audio is passed through the link to the voter.
The pilot tone from the PTG-10 can also function as a line proving tone to insure the integrity of
the audio link in the following way: the removal of the pilot tone on the link notifies the voter
to begin looking for voice signals from the voting receiver. If the voter doesn’t sense voice
coming from the receiver within a programmed time, it faults that particular voting site on the
assumption that either the voting receiver is not functioning, or the link is broken between the
receiver and the voter. The SNV-12 disallows use of that voting input until voice is received
from the distant receiver or until the pilot tone returns.
The PTG-10 is capable of injecting either of two user selectable pilot tones: 1950 Hz or 2175 Hz.
The module is 6.84" x 2.42" x 1.2" and is enclosed in a metal box suitable for mounting to any
flat surface or to a standard 19" rack. The mounting tabs are designed such that bolting three
units together side by side will span the standard 19" size rack. System interconnections are

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made by wiring to a screwdriver type terminal block. Audio input from the receiver is
unbalanced, while audio output to the voter is configured for 600 Ohm balanced operation. The
terminal block has provisions for a COR input (either positive logic “COR” or negative logic
“/COR”), power input (+11 to +15 VDC) and ground. Two LEDs are provided: One indicates
the when a pilot tone is being mixed; the other is a power indicator. The pilot tone level and the
audio output level (voice plus pilot tone) are independently adjustable.
1.2.2 Circuitry and Block Diagrams
Refer to Figure 5-1. JP1 is the terminal block that interfaces all inputs and outputs between the
PTG-10 and the outside world. Audio enters the unit from a receiver at terminal 4 with respect
to ground, terminals 1 and 7. This audio is mixed at the mixer amp with the tone produced by
the tone oscillator. Tone frequency selection is made using switch SW1. Placing the switch in
position (0) will yield a 2175 Hz tone. Position (1) will yield a 1950 Hz tone. The pilot tone and
receive audio tones are sent the final amp stage which controls the output level. The output is
sent to a matching transformer for balanced 600 Ohms. When the unit receives a COR signal on
terminal 2 or a /COR signal on terminal 3 the tone is removed from the audio chain. When the
unit receives a COR signal (positive or negative) the yellow COR led will illuminate. The
balanced output is sent to pins 5 and 6 of JP1.
1.2.3 Mechanical Assembly
Please refer to Figure 2-1. This drawing shows the front of the unit with rack mount tabs on each
side plus the drawing shows the side, top and bottom views. The rack mount tabs enable the unit
to be bolted to one side (either side of unit) of a standard 19" rack, possibly on the rear of the
rack behind other equipment. Another option is bolting three of the units together side by side:
this will span the standard 19" rack enabling mounting to the rack at both ends. The unit consists
of a ‘C’ shaped top cover that is attached by two screws to the main chassis. The circuit board
is secured to the chassis via four standoffs.
1.2.4 Function and Operation
Please refer to Figure 5-4. The PTG-10 enables two conductors to carry both an audio signal and
a COR signal. The PTG-10 can also function as a line proving tone to insure the integrity of the
audio link. The tone produced by the PTG-10 will be notched out in the voter. Two LEDs allow
status monitoring. A green LED indicates if the system is getting power, and an amber LED
indicates when the system is mixing a pilot tone with the throughput RX audio. The unit will
accept either positive or negative logic. Whenever the PTG-10 COR inputs gate the pilot tone.
When COR is inactive, the PTG-10 outputs pilot tone. This audio plus pilot tone signal can be
sent to a voter via a microwave link, leased lines or twisted pair.
1.2.5 Power Supply
Power is fed into the unit via pin 8 of JP1 and ground on pins 1 and 7; this is shown on Figure
5-1 and Figure 5-3. The unit produces three different voltage supplies, +12 VDC, +5 VDC, and
- 10 VDC. Under normal conditions the system should draw approximately 40 mA. The input
is reverse polarity protected. If the power polarity is accidentally reversed, the unit will not
operate, but it will not be damaged.
1.2.6 Limitations
The PTG-10 audio input is single-ended rather than balanced (to match the RX output signal of
many receivers). The PTG-10 should be placed near the receiver so that the common mode

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rejection that a balanced link provides is not needed on the input signal. In contrast, the unit’s
audio output is balanced, as the output is likely to be sent over a long distance.
Table 1-1 SPECIFICATIONS
Electrical
DC Input Power
+12VDC ranging from +11 to +15 VDC @ 40 mA
Input Impedance
50K ohms unbalanced
Output Impedance
600 ohms balanced
Frequency Response
Conservatively rated: 50 to 20 kHz +/-2 dB.
Tone Frequencies
1950 Hz or 2175 Hz, switch selectable
Tone Stability
+/-2 Hz.
The following are referenced to 0 dBm output:
Receiver Audio Input Range
-20 to +4 dBm, variable
Pilot Tone Output Level
-20 to +9 dBm, variable
General
Indicators
LED Indicators: Power On, Tone Present
Front Panel Controls
Power On/Off Switch
Size
6.84x2.42x1.19
Weight
0.5 lbs.
Environmental
Operating Temperature
-20 degrees C to +55 degrees C.
Storage Temperature
-40 degrees C to +85 degrees C.
Humidity
Up to 95% at 55 degrees C.
Table 1-2 EQUIPMENT AND ACCESSORIES SUPPLIED
Qty
Item
JPS Part Number
1
PTG-10
5970-900000
1
Operation & Maintenance Manual
5970-900200
1
Accessory Kit
5970-900150
Accessory Kit consists of:
Qty
Item
JPS Part Number
4
Washer, Flat Nylon
0848-100001
4
Screw, 10-32x3/8
0837-103200
2
Nut, 10-32
0828-103200
2
Split Washer, 10-32
0851-100000

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2-1
2Installation
2.1 General
This section provides the instructions for unpacking, inspection, installation and set-up. Also
included are directions for reshipment of damaged parts or equipment.
2.2 Unpacking and Inspection
After unpacking the unit, retain the carton and packing materials until the contents have been
inspected and checked against the packing list. If there is a shortage or any evidence of damage,
do not attempt to use the equipment. Contact the carrier and file a shipment damage claim. A
full report of the damage should also be reported to the JPS Customer Service Department. The
following information should be included in the report:
1. Order Number
2. Equipment Model and Serial Numbers
3. Shipping Agency
4. Date(s) of Shipment
The JPS Customer Service Department can be reached by phone at [phone], by fax at
[phone]. Upon receipt of this information, JPS will arrange for repair or replacement of
the equipment.
2.3 Reshipment of Equipment
If it is necessary to return the equipment to the manufacturer, a Returned Material Authorization
(RMA) number must first be obtained from JPS. This number must be noted on the outside of
the packing carton and on all accompanying documents. When packing the unit for reshipment,
it is best to use the original packaging for the unit; if this is not possible, make sure that adequate
packing material is used to prevent excessive shocks during transport and handling.
Shipment should be made prepaid consigned to:
JPS Interoperability Solutions, Inc.
Customer Service Department
5800 Departure Drive
Raleigh, North Carolina 27616
USA

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Plainly, mark with indelible ink all mailing documents as follows:
GOODS RETURNED FOR REPAIR
Mark all sides of the package:
FRAGILE - ELECTRONIC EQUIPMENT
Inspect the package prior to shipment to be sure it is properly marked and securely wrapped.
2.4 Installation Overview
Three quick and simple steps are needed to properly install the PTG-10. These steps are:
1. Provide mechanical mounting for the unit
2. Provide the proper DC power for the unit.
3. Interconnect the unit with the communications system via the unit’s JP1 connector.
The PTG-10 is then ready to begin normal operation.
2.5 Installation Considerations
Careful attention to the following installation suggestions should result in the best unit/system
performance. Figure 2-1 provides overall unit dimensions.
The PTG-10 must be installed in a structure that provides both protection from the weather and
assurance of ambient temperatures between -10 and +55 degrees C. Since the unit is neither
splash proof nor corrosion resistant, it must be protected from exposure to salt spray.
NOTE: The PTG-10 is designed to be mounted in a standard EIA 19" wide rack
by means of attaching the unit to the rack on either side or bolting three units
together to span the entire rack. Screws are provided in the accessory kit for
securing the unit to the rack via the front panel.
2.6 Power Requirements
The PTG-10 is designed to operate from +11 to +15 VDC. Power consumption is 0.5 VA typical.

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2.7 Configuring the PTG-10
This section explains how to set and adjust all internal jumpers and potentiometers.
2.7.1 Jumper Settings
There are two tone frequencies available depending on the setting of SW1. Placing the switch in
position (0) will produce a 2175 Hz tone; position (1) will produce a 1950 Hz tone.
2.7.2 Potentiometer Adjustments
The PTG-10 has two factory set potentiometers. See Figure 2-1. “Overall Adjust” (R8) is set so
that a -10 dBm input will produce a 0 dBm output. “Pilot Adjust” (R4) is also set for 0 dBm
output. These settings are made with a 600 ohm load across output pins JP1-4 and JP1-5. Both
potentiometers can be re-adjusted to fit specific applications. The SNV-12 voter will work best
with the pilot tone at the same level as the overall audio. The SNV-12 will completely notch out
the pilot tone so that the tone will never be heard at the console or re-transmitted. Also, the high
relative pilot tone level ensures that the voter will easily detect it even when there is a large
amount of high-frequency roll-off in the line from the receiver to the voter.
When adjusting the overall receiver audio level, make sure that one of the COR inputs is
activated. If not, the pilot tone will be mixed with the receiver audio during the adjustment. The
simplest method is to ground pin 3 of JP1 (/COR) to remove the pilot tone. Note that the overall
level adjust (R8), controls the levels of both the receiver audio and pilot tone. As set at the
factory, the pilot tone is at the same level as the receiver audio level. If only R8 is readjusted,
the pilot tone will maintain the same relative level. If audio levels different from the factory
settings are required, always set the overall level first with R8, then adjust the relative pilot tone
level with R4.

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2.8 Interconnect Information
2.8.1 Input and Output Connections Plus Power and Ground
All external connections are made via wires that enter the unit through a grommet located on the
side of the chassis. The wires are connected to JP1 as shown in Table 2-1.
2.9 Setting Levels
The unit is factory set for the audio input level from the receiver to be -10 dBm and the audio
output level of the PTG-10 to be 0 dBm. The PTG-10 is also factory set for the pilot tone level
to be 0 dBm. Below is the procedure for setting the levels of the receive and pilot tone audio on
the PTG-10:
Please refer to Figure 5-2.
1. Connect the receiver audio to the PTG-10 as shown. Either COR or /COR may be
used. The COR input produces a tone when a high signal is present. /COR produces
a tone when a low input signal is present.
2. Place a 1 kHz reference test tone (3 kHz deviation wideband / 1.5 kHz narrowband)
into the receiver antenna input.
3. Adjust R8 for the desired audio output level measured across pins 5 and 6.
4. Remove the test tone from the receiver so that the receiver squelches; then adjust R4
for the desired tone level.
Table 2-1 JP1-Input/Output Connector
Eight way screw driver terminal block.
Pin
Signal
1
Ground
2
COR Input
3
/COR Input
4
Unbalanced Audio Input
5
Balanced Audio Output A
6
Balanced Audio Output B
7
Ground
8
+11 to +15 VDC Power Input

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Figure 2-1 –Outline Dimensions
A
A
B
A
B
A
2.50 1.25
0.63
5.24
6.84
NOTES:
A. 19" RACK MOUNT SLOTS (.45 X .25 DIA.)
B. OPTIONAL MOUNTING HOLES .166 DIA.
1.19

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Figure 2-2 –Locations of Indicators and Adjustments

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3-1
3Operation
3.1 General
This section contains information and instructions required for proper operation of the PTG-10.
3.2 Operational Indicators
3.2.1 Power Indicator
This green LED, which can be viewed through a slot in the top cover, is illuminated whenever
the unit’s main power is on and the power supply circuitry is functioning correctly.
3.2.2 Tone Indicator
This amber LED, situated next to the Power Indicator LED, is illuminated whenever the unit is
receiving an active COR signal (high signal for COR input, low signal for /COR input) and as a
result is outputting a pilot tone.
3.3 Operation
Once this unit is connected to the system and the levels are properly adjusted, the device will
operate on its own and requires no user intervention.

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4-1
4Theory of Operation
4.1 General
This section gives enough detail about the theory of operation in regard to the audio and power
supply sections to allow them to be trouble shot in the field.
4.2 Tone Circuit
Refer to Figure 5-1. Terminal block JP1interfaces all inputs and outputs between the PTG-10
and the outside world. Receiver Audio enters the unit at terminals 4 (RX In) and 1 or 7 (ground).
This audio is routed to a mixer amp; where it can be mixed with a pilot tone.
The tone oscillator circuit generates the pilot tone. A microcontroller circuit outputting data to a
D/A converter generates the pilot tone. The tone is produced using an ATMEL AVR Mega8L
micro controller. The Mega8L reads the status of the tone selector switch (SW1) and constantly
monitors both the COR and /COR input. When either an active low signal is detected on the
/COR input or an active high signal is detected at the COR input, the Mega8L produces the pilot
selected via switch SW1. The Mega8L generates the proper asynchronous serial data, sync line
and clock for the D/A to produce the analogue equivalent to the outputted data. The D/A output
is then sent to a Sallen-Key Butterworth filter to remove all of the composite harmonic energy.
The result is a clean sine wave at the selected frequency.
The output of the filter circuit is sent to the tone level POT R4. The tone level is adjustable from
-20 dBm to +9 dBm via R4 (this level can be measured at test point TP4). The tone is now mixed
with the receiver audio in an op-amp mixing circuit (U2A) where it is routed to the output stage
consisting of an inverting amplifier with a level control in the feedback loop. The output of the
mixer circuit can be observed at test point TP2. The value of this pot in the feedback loop is
balanced with the value of the input resistor to give a range of 30 dB from -30 to +4 dB of gain.
The balanced output is sent to pins 5 and 6 of JP1. The final output can be seen with an
oscilloscope on test point TP1.
4.3 Power Supply
Power is fed into the unit via pin 8 of JP1 and ground on pins 1 and 7; this is shown on Figure
5-1 and Figure 5-3. The input power needs to be in the range of +11 to +15 VDC for the unit to
function. The input voltage is filtered and then sent in three directions. First, the input voltage
is sent directly as +12 VDC nominal (actual range is +11 to +15 VDC). It’s also sent to a five-
volt regulator, and to a positive to negative converter producing -10 VDC. The positive to
negative converter works as follows, the incoming +12 VDC is inputted into a 555-timer chip.
The output is a 12 VDC square wave, the square wave is sent to a diode pump made up of CR1
and CR2. The diode pump working in combination with C27 a 470 uF cap forms a -10 VDC
supply. Under normal conditions the unit should draw approximately 40 mA.

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5-1
5Maintenance and Repair
5.1 General
This section gives enough detail about the theory of operation in regard to the audio and power
supply sections to allow them to be trouble shot in the field.
5.2 Preventive Maintenance
There are no preventive or periodic maintenance requirements for this equipment.
5.3 Repair or Replacement
The repair or replacement of damaged and/or defective parts generally requires techniques that
are standard in the industry. Carefully examine the equipment to determine the most correct and
least time-consuming method required to make the repair.
5.3.1 General Precautions and Notes
1. Disconnect power from the unit before attempting any repair or replacement of
components.
2. Replace defective connectors only with identical items.
3. Carefully observe lead dress and component orientation when repairing circuits. Keep
component leads as short as possible.
4. Reference to the component side of a printed circuit (pc) board denotes the side of the
board on which the majority of components are mounted. The solder or circuit side refers
to the side opposite the components.

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Figure 5-1 –Circuit Diagram 1
Header 8
-10 Volt
Converter
5 Volt
Regulator
DAC
Mega 8L
Micro Controller
1
2
JP1
3
4
5
6
7
8
COR
ISP HEADERS,
JP4, JP5
RS-232
DB-9
P1
Overall Level
Adjust-
-4 to +20dB Gain
Mixer
Amp
Tone Level
Adjust-
-25 to +9dB Gain
+12VDC
+5VDC
-10VDC
/COR
Vin
Vin
Balanced Output B
Balanced Output A
Unbalanced Input
VCC
AMBER
TONE PRESENT
SW 1
TONE
SWITCH