User manual

MPX BOARD CONNECTIONS (FM VERSION ONLY)

ENG

Page 22

The MPX OUT 1 (BNC connector) provides the FM composite signal + any RDS signal

(internally generated or injected from an external encoder) and SCA signal.

The MPX OUT 1 TEST

connector provides a repetition of the output signal appearing at

the main MPX OUT 1 connector, with the same level

. The TEST output is individually

buffered so that a short circuit on one output will not affect the other. The TEST output is

mainly designed to allow easy and fast measurement on the main MPX signal being

output by the processor, without alterating it.

An hardware bypass directly connects the AUX-1 connector to the MPX OUT-1 connector in the event

of Main AC failure. The hardware bypass is achieved through the Relè 1 (see block diagram).

Remarks:

- The stereo multiplex output level is adjusted by a rear panel multiturn precision trimmer. The level is adjustable from

-inf to +12dBm (8.8 Vpp) at 100% modulation. Factory preset is 0 dBm, i.e. approximately 2.2 Vpp.

- The output impedance of the BNC jack is approximately 10 ohms sourced by an output driver capable to drive 600

Ohm loads (typical). Maximum performance is achievable when using up to 10 meters of RG-58 cable. Alternatively,

75 Ohm cable may also used for short runs.

- Contrary to Left / Right audio outputs, pre-emphasis is always present on the MPX output and you can NOT

disable it. Nevertheless, the menu allows you to set the pre-emphasis time to 50 or 75μ sec. (see par 25.2).

- The 19 kHz pilot phase and level may be adjusted via the menu (25.3).

- MPX Out provides a reference tone consisting of a 400 Hz / 0 dBm signal + pilot tone of 19 kHz / - 20 dBm. This

tone corresponds to the maximum frequency deviation of 75KHz. To enable the reference tone, see chapter 27.

- The processor has a built-in automatic composite clipper, not adjustable by the user.

The SYNC OUT (BNC connector) outputs a 19KHz / 5Vpp square wave for external equipment synchronization (i.e. RDS

encoders). The Sync output must be enabled via the menu (Optional Controls / MPX Mode / Sync Out).

The MPX OUT 2 (BNC connector) is shipped DISABLED unless the MPX – SPLIT option is

installed. That option must ne requested at the order.

Refer to Chapet 16 for further reference on the SPLIT option.

MPX

Out