Aeroflex Circuit Technology

SCD4810 REV B 8/12/98

Plainview NY (516) 694-6700

2

70 Ohm terminations plus additional

receivers,

the

data

bus

signal

produced is 7.5 volts nominal P-P at

A-A’. (See Figure 5) When both

DATA and DATA inputs are held low

or

high,

the

transmitter

output

becomes a high impedance and is

“removed” from the line. In addition,

an

overriding

“INHIBIT

input

provides for the removal of the

transmitter output from the line. A

logic “1” applied to the “INHIBIT”

takes priority over the condition of

the data inputs and disables the

transmitter. (See Transmitter Logic

Waveform, Figure 1.)

The transceiver utilizes an active

filter to suppress harmonics above

1 MHz to meet Macair specifications

A-3818,

A-4905,

A-5232

and

A-5690.

The Transmitter may be

safely

operated

at

100%

duty

cyclefor an indefinite period into a

short circuited, the 1553 or Macair

bus.

Receiver

The

Receiver

section

accepts

bi-phase differential data at the input

and produces two TTL signals at the

output. The outputs are DATA

and

DATA, and represent positive and

negative excursions of the input

beyond

a

pre-determined

threshold.(See

Receiver

Logic

Waveform Figure 2).

The pre-set internal thresholds will

detect data bus signals exceeding

1.150 Volts P-P and reject signals

less than 0.6 volts P-P when used

with a 1:1 turns ratio transformer.

(See Figure 5 for transformer data

and typical connection.)

DATA IN

DATA IN

INHIBIT

LINE TO LINE

OUTPUT

NOTES:

1. DATA and DATA inputs must be complementary waveforms or 50% duty cycle average, with no delays between them.

2. DATA and DATA must be in the same state during off time (both high or low).

Figure 1 – Transmitter Logic Waveforms

Figure 2 – Receiver Logic Waveforms

Note overlap

the receiver outputs are swapped as shown by the dashed lines.

,

level devices,

LINE TO LINE

INPUT

DATA OUT

DATA OUT