RF Technology R150 Betriebsanleitung PDF herunterladen (Seite 8)

Page 8 RF Technology T70/T150

JP17 Bypass Low Pass Filter 2 TRANSMITTER INTERNAL JUMPER OPTIONS

excessive pulse edge distortion of the trunking controller’s digital signals. In such

circumstances, JP16 allows a user to bypass the low and high pass filters in the tone

input section. See also 2.12 - JP22: If direct tone input is selected, then JP22 should

be removed (open).

Condition Position

Normal Tone Input 1-2*

Direct Tone Input 2-3

2.10 JP17: Bypass Low Pass Filter (Rev 4 or higher)

Some trunking controllers have digital encoding schemes that require the low pass

filter in the tone input section to be bypassed. JP17 allows this. Normally JP17 is

open circuit. Placing a link across it will bypass the low pass filter.

In conjunction with this change, it sometimes may be necessary, depending on the

type of trunking controller used, to add a 100K resistor in the place reserved for R157.

2.11 JP19: Alarm Output (Rev 4 or higher)

The main audio transformer (T1), is connected to the Line IP1 and Line IP4 pins on

P3.

These two pins constitute the main audio input for the exciter. The centre taps of the

audio transformer, though, are brought out on Line IP2, and Line IP3. These can be

used as alternate audio pins for larger signals, or to directly access the dc loop sense

circuitry. JP19 allows an alternate use for Line IP2 (pin 7 of P3). In the alternate

position for JP19, the ALARM signal (the signal that drives the ALARM LED itself)

is connected to pin 7 of P3. The ALARM signal when asserted is low active; when

unasserted, it pulls high to +9.4V through an LED and a 680 ohm resistor.

Condition Position

P3, pin 7 connects to center tap of transformer T1 1-2*

P3, pin 7 connects to ALARM signal 2-3

2.12 JP22: Use Tone- as a Direct Digital Input (Rev 4 or higher)

JP22 is normally shunted with a jumper, which connects Tone- on P3 (pin 18), as the negative

leg of the Tone input pair. Removing this jumper disconnects Tone- from this path and allows

the use of the Tone- pin to be used as a direct digital input. See also 2.9 - JP16: If this jumper is

removed, then JP16 should be in the alternative position (Direct Tone Input).

2.13 JP23: Connection of DMTX Board (Rev 4 or higher)

When a DMTX board is connected to an exciter, there is provision for digital or audio

modulation of the reference osciallator and the VCO. The digital signal is input via the DB9

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RF Technology R150 Betriebsanleitung Seite 8