JPS PTG-10, Installation And Operation Manual, Page: 6 / 26

PTG-10 Operations Manual
1-2
Interoperability Now!
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