CT1698 Datasheet, PDF (2/7 Pages) Aeroflex Circuit Technology – CT1698 MIL-STD-1397 Type E 10MHz Low Level Serial Interface

Transmission
The CT1698 accepts synchronous NRZ Data in
conjunction with two clocks signals. The NRZ data
stream is then converted to Manchester code which
is transformer coupled to a 50 ohm Tri-axial cable for
transmission up to 1000 ft.
The transmitter may be placed into standby
condition. This reduces power consumption by
approximately 600mW. Power management is made
available via two standard TTL input pins. The
Receiver is always active and is not affected by the
power management circuitry.
The drive level of the transmitter may be changed
by adding external resistors to the drive pins. These
pins allow the designer to externally program the
transmitter output level from 0.7 to 2.8 Volts peak to
peak.
The transceiver is matched for 50 ohm operation
over a wide band of frequencies. This condition is
maintained with power on and off.
Reception
The CT1698 receiver section accepts a bipolar
signal which is level detected and passed to the
serial decoder. The decoder section reconstructs
the data and strips the clock from the serial stream.
An NRZ decoded data stream is then produced
synchronously with a recovered clock. The receiver
is designed to meet the MIL-STD-1397 Type E
requirements.
Electrical Requirements
The specification detailed herein encompasses a
hybrid Transceiver/Encoder-Decoder designed to
meet the requirements of the MIL-STD-1397 Type E.
The transceiver is transformer coupled to the
specified triaxial cable.
See Figure 1 for Block Diagram. Inputs and
Outputs are all Synchronous NRZ DATA STREAMS.
The transformer is internal to the package with its
use being optional.
Encoding Timing / Transmitter Specification
Symbol
Encode Timing
t1
t2
t3
t4
t5
t6
tw1
tw2
Output Signals
Va
T
Ts
Te
T/2
Tr
Tf
Vs
Tos
Tdtx
Zo
Parameter / Condition
Input data set-up time
Encode clock set-up time
Encode envelope set-up time
Encode envelope turn-off time
Transmitter activation set-up time
Transmitter deactivation hold-time
20 MHz gated CK pulse width high
Encoder shift CK pulse width high
Output amplitude (see Figure 2)
Pulse period
Width of 1st positive half bit
Width of last half bit
Half pulse period
Pulse rise time
Pulse fall time
Voltage overshoot
Offset Voltage 2T after last zero crossing
Delay from 20 MHz clock input to data output on
TXFMR secondary
Output Impedance
Min Typ Max Unit
10
40 ns
10
40 ns
10
40 ns
10
35 ns
100
ns
50
ns
20
30 ns
45
55 ns
.45 .7 .8 V
97 100 103 ns
45
65 ns
47
65 ns
47 50 53 ns
.05
.3 V/ns
.05
.3 V/ns
100 mV
30 mV
20 55 ns
45 50 55 Ω
Aeroflex Circuit Technology
2
SCDCT1698 REV A 6/12/98 Plainview NY [phone]