DRAKE FMC 1000 Instruction Manual - Page 9

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1. Introduction - General Description

MADE IN U.S.A.

R F O U T P U T

D C I N P U T

P O W E R

OFF

12 VDC

250 mA

1. DC INPUT - Connect the supplied AC Adapter to this

connector. Secure AC Adapter DC cable with the

adjacent rear panel strain relief.

2. POWER ON/OFF Switch - Set this switch to the 'ON'

position to operate the FMC 1000.

3. RF OUTPUT - This is the modulator output.

4. LIMITING/COMPRESSION SWITCH - This switch

selects the operation of the limiter. Select the proper,

or desired, setting according to the following criteria:

"OFF" - For audio sources with limiting and/or compres-

sion already applied. This setting bypasses the limiting

circuitry of the FMC 1000. With the audio source

connected, adjust the INPUT LEVEL control to a setting

at or just below the point where the (OVER) MODULA-

TION indicators light on audio peaks.

"L" - For most types of audio sources and listening

environments. This setting provides automatic limiting

on audio peaks to prevent loud bursts and to avoid

over modulation conditions which can cause distorted

audio at the receiver. With the audio source con-

nected, (for example, the output of a public address

amplifier with a person speaking at a normal level into

the microphone), adjust the INPUT LEVEL control to a

setting at the point where the (OVER) MODULATION

indicators light on audio peaks.

"C+L" - For audio sources that contain relatively low

audio levels combined with relatively high audio levels

as might be encountered when the audio output from a

public address amplifier contains audio from multiple

microphones with different persons speaking. This

setting provides automatic increasing of the low level

audio passages combined with limiting on voice peaks.

This type of audio processing can sometimes aid

intelligibility for a person receiving the signal while

located in a relatively noisy audio environment. With

the audio source connected, and the weaker audio

levels active, adjust the INPUT LEVEL control to a

setting at or just below the point where the (OVER)

MODULATION indicators light on audio peaks.

5. LEFT AUDIO INPUT - Connect monaural audio input

signals to the appropriate unbalanced or balanced

LEFT AUDIO INPUT connector. For monaural input,

program the FMC 1000 to display 'MONO'. See Item 5;

'TUNE

Buttons' in the 'Front Panel Controls and

Indicators' section of this manual.

Rear Panel Controls and Connections

L I M I T I N G /

C O M P R E S S I O N

OFF

C + L

L E F T A U D I O

I N P U T

(MONO)

20K

UNBALANCED

BALANCED

16 TO

4dBu

10 TO

10dBu

For stereo input, connect an unbalanced line level left

channel stereo audio signal to the phono connector or

connect a balanced line level left channel stereo audio

signal to the 3-pin female XLR connector. The unbal-

anced phono style input and the XLR balanced input

on a given input (Left or Right) are each always active,

so audio will be fed from whichever input is being used.

Do not attempt to connect signals to both the

unbalanced and balanced connectors on a given

input (Left or Right). All inputs can be considered high

impedance (>20K Ohm). The shield connection at pin

1 of the XLR connector can be conveniently connected

to ground (GROUND LIFT = 'OFF') or lifted from ground

(GROUND LIFT = 'ON') to eliminate hum or noise as

required. For stereo input, program the FMC 1000 to

display 'STEREO'. See 'Front Panel Controls and

Indicators: See Item 5; 'TUNE

'Front Panel Controls and Indicators' section of this

manual.

6. GROUND LIFT Switch - Set to the 'OFF' position to

connect pin 1 of both LEFT and RIGHT XLR connectors

to ground. Set to the 'ON' position to disconnect both

XLR connectors from ground.

7. RIGHT AUDIO INPUT - For stereo input, connect an

unbalanced line level right channel stereo audio signal

to the phono connector or connect a balanced line

level right channel stereo audio signal to the 3-pin

female XLR connector. Never connect signals to both

the unbalanced and balanced connectors on a given

input (Left or Right).

The shield connection at pin 1 of

the XLR connector can be conveniently connected to

ground (GROUND LIFT = 'OFF') or lifted from ground

(GROUND LIFT = 'ON') to eliminate hum or noise as

required. For stereo input, program the FMC 1000 to

display 'STEREO'. See Item 5; 'TUNE

the 'Front Panel Controls and Indicators' section of

this manual.

Connect a monaural audio signal to the appropriate

LEFT AUDIO INPUT connector. See Item 5: 'LEFT

AUDIO INPUT', on this page.

8. Access Hole for RF OUTPUT Level Adjustment -

The RF output level can be reduced to a value approxi-

mately 10 dB below the nominal level by adjustment of

the potentiometer. The potentiometer is tunable

through the access hole. Use a small straight-slot type

screwdriver to adjust the potentiometer, if adjustment is

necessary. Counterclockwise rotation of the potentiom-

eter decreases the output level.

GND

R I G H T A U D I O

HIGH

I N P U T

LOW

G R O U N D

L I F T

20K