Meinberg TCR511PEX Bedienungsanleitung PDF herunterladen (Seite 13)

Input impedance

The IRIG-specification doesn’t define values for the output impedance of generators or

the input impedance of receivers. This fact led to incompatibility of some modules,

because the manufacturers could choose the impedances freely. For example: if the

output impedance of the generator is high and the input impedance of the receiver low,

the signal level at the receiver input might be too low for correct decoding. Therefore the

board TCR511PEX contains a jumper to select the impedance (50 Ω, 600 Ω or 5 kΩ) of

the input for modulated codes (BNC) to comply with the requirements of several

systems.

Meinberg IRIG-generators have an output impedance of 50

ΩΩ

Ω, to build a matched

transmission system when using a coaxial cable. If such a generator is used to synchroni-

ze TCR511PEX, the input impedance has to be set to 50 Ω accordingly (default on

delivery).

In addition to the telegram, the AFNOR-code defines the input/output impedances

also. If TCR511PEX is synchronized by this code, an input impedance of 600

Ω Ω

Ω must be

set.

The setting „5 kΩ“ may be necessary if the generator has a high output impedance (see

specifications of manufacturer). The driver software shows a bar chart for evaluation of

the signal level at the receiver input.

The following detail of the placeplan of TCR511PEX shows the possible jumper

setting with the related input impedance:

No jumper set: 5K Ohm

Jumper in this Position: 50 Ohm

Jumper in this Position: 600 Ohm

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Meinberg TCR511PEX Bedienungsanleitung Seite 13