Print Date 04/01/11 Page 22 of 42 E2165-00MA-04
2.2.10 Left and Right Audio Input Connectors (/S Stereo Encoder version only)
These are two three pin XLR sockets at the rear of the unit (fitted to the rear of the /S Stereo Encoder
module) used for interconnection to stereophonic modulating signal (or monophonic using a single
input). Twin, separately screened cables, not exceeding three metres in length, should be used for the
interconnecting leads.
Each lead terminates in a three pin XLR plug at the Exciter end which is wired as follows :-
Pin 1
Direct chassis ground – or,
Chassis ground via 150n/50V capacitor
Pin 2
Signal (+)
Pin 3
Signal (-)
The input impedance can be set internally to balanced 600
Ω
or 20k
Ω
with pin 1 either connected
directly to chassis ground or via a capacitor (see E2165-00GA). The input sensitivity of each input is
set separately using the adjacent rear panel controls, with pre-emphasis set from the front panel to
none, 25uS, 50uS or 75uS.
Input sensitivity for
±
67.5kHz deviation (exc. pilot) at 400Hz :+8dBm (600
Ω
input) :+8dBu : 5.5V p to p
(maximum sensitivity approximately : -4dBm (600
Ω
input) : -4dBu : 1.4 peak to peak)
Note that each input can be made unbalanced by externally connecting one of the balanced signal
input lines to ground (pin 2 or pin 3 to pin 1). The input impedance then becomes 600
Ω
or 13.3k
Ω
.
2.2.11 Pilot Output Connector (/S Stereo Encoder version only)
This is a 50
Ω
SMA coaxial socket SK14 at the rear of the unit used for interconnection to external
equipment, typically RDS generators, which generate a sub-carrier which requires phase locking to
harmonics of the Stereo Encoder, 19kHz, pilot tone (57kHz in the case of RDS). An SMA plug is used
for connection to this output, with matching screened coaxial cable, not exceeding three metres in
length. The output is approximately 100
Ω
, at a level of 5V peak to peak, sinewave (open circuit).
2.2.12 COM Port Connector
This is a 9 Way D plug PL11 on the rear panel. This enables all the control and monitoring, detailed in
Section 2.4, to be performed using a personal computer with its (RS232) COM port connected to this
port. Multi-core screened cable, not exceeding 30 metres in length, should be used for the
interconnecting lead. The lead terminates in a 9 Way free D socket at the Exciter end which is wired
as follows :-
Pin 1
Not connected
Pin 2
Received Data (to Exciter)
Pin 3
Transmit Data (from Exciter)
Pin 4
Not Connected
Pin 5
Ground
Pin 6
Not Connected
Pin 7
Not Connected
Pin 8
Not Connected
Pin 9
Not Connected
Note that the assigned pin numbers and their functions are for a standard 9 pin plug on ‘Data Terminal
Equipment’ (DTE) such as computers. Standard crossover or ‘null modem’ leads must thus be used
for connection to a personal computer or PC. The length of the interconnecting lead may be extended
by use of compatible RS422/485 or fibre-optic line drivers.
Note that an internal lead connection determines if serial control and monitoring is via this RS232
connector or via the rear panel TCP/IP connector SK04 (see 2.2.7). For RS232 control, the 3 pin
screened lead from the Front Panel board connector (6)CON05 must be plugged into the Input/Output
Board connector (14)CON03 (see E2165-00CT).
