T-7l5 Transmitter - L

T-7l5
Transmitter
The L-3 Communications Cincinnati Electronics model T-715 Transmitter for satellites is an S-Band spread
spectrum Transmitter that is compatible with the TDRSS Multiple Access Return Service. The T-715 unit
can be configured to have Forward Error Correction (FEC) enabled or disabled. The unit can also enable
or disable the Pseudo Random (PN) spreading code. The T-715 unit supports TDRSS Data Group 1
mode 2 and TDRSS Data Group 2 modes.
Health and status telemetry is provided
in an analog format and discrete RS-422
differential digital mode control commands are provided. All signal interfaces
with the spacecraft are via a 25 pin male
D-shell connector, identified as J2. All digital signal interfaces are compatible with
encrypted data provided by the KG-228
(RS-422 is available).
The Transmitter RF Nominal output
power is greater than or equal to, +38.0
dBm over operating temperature of
-24˚C to +55˚C and over mission life. The
impedance at the Transmitter output
connector is 50 ohms nominal with a
maximum Voltage Standing Wave Ratio
(VSWR) of 1.5:1 over the frequency range
of Ft ±6 MHz.
The unit is designed such that the
average thermal dissipation density
through the baseplate does not exceed
1 watt/in2. The Transmitter is designed
for continuous operation from atmospheric pressure to full vacuum and is
designed and fabricated to prevent the
formation of corona, multipaction, or
arc discharges.
The Transmitter operates from a voltage
source of 28 volts ±6 volts. The power
interface is via a 9 pin male D-shell connector, identified as J3. The Transmitter
circuits are powered whenever prime
power is present.
The Transmitter provides a balanced (I/Q
power ratio is 1:1) spread spectrum SQPSK
modulation. Prior to the SQPSK modulation, the I and Q channels consists of
identical data with data rates between 1-60
kbps that is synchronous NRZ-M formatted
and rate 1/2 convolutionally encoded per
530-SNUG for DG1 mode 2.
Performance and Functionality
The T-715 accepts one Non-Return-To-Zero Level (NRZ-L) Transition
Transistor Logic (TTL) digital data stream compatible with KG-228
encrypted data output per ON636335 Rev. B. The unit converts data
from NRZ-L to Non-Return-To-Zero Mark (NRZ-M) data format and
convolutionally encodes rate1/2, K=7 encrypted serial data per
530-SNUG. PN Code Spreads (Chip) the NRZ-M convolutionally
encoded serial data per 530-SNUG.
Specifications
T-715
PERFORMANCE CHARACTERISTICS
TELEMETRY INTERFACE CHARACTERISTICS
Frequency
Frequency Stability
OP_T (POut)
RP_T (PReflected)
+9 Vdc Supply
Frequency Reference
Antenna Impedance
Power Output
Modulation
Phase Imbalance
Amplitude Imbalance
Data Rate
2287.5 MHz (S-band)
±0.5 ppm (0˚ to +50˚C)
±1 ppm (-24˚ to +55˚C)
TCXO provides stable reference
to low phase noise PLL
≤ 5 degrees rms 1 Hz -10 Hz
≤ 2.5 degrees rms 10 Hz - 3 MHz
50 ohms nominal (≤ 1.5:1)
+38.0 dBm (-24˚ to +55˚C) and
mission life
QPSK (I Channel leads the Q
Channel by 1/2 of a chip)
≤ 5 degrees
≤ 0.25 dB
1 to 60 kbps
SINGLE INTERFACE CHARACTERISTICS
Tx_Data
Tx_Clk
FEC On/Off
PN On/Off
ON636335 or RS-422 Compatible
ON636335 or RS-422 Compatible
RS-422 Differential
RS-422 Differential
5 Vdc Analog
5 Vdc Analog
4.5 Vdc Analog
POWER REQUIREMENTS
Input Voltage
Input Power
+28 Vdc ±6 Volts
37 Watts Max
ENVIRONMENTAL SPECIFICATIONS
Temperature
Vibration
Altitude
-54˚C to +75˚C (nonoperating)
-24˚C to +55˚C (operating)
Random; 9.74grms, 3-axis
Unlimited
PHYSICAL
Volume
Weight
Mounting
7.0” x 5.4” x 3.4” (128.5 cu. in)
< 4.9 lbs. (12.17 kg)
0.281 Diameter Through Hole
T-715 Outline Drawing
Space Electronics ~ 7500 Innovation Way ~ Mason, Ohio 45040-9699 U.S.A.
Tel: 1-513-573-6994 ~ Fax: 513-573-6767 ~ Visit our web site at www.L-3com.com/CE~ e-mail: [email protected]
Cleared by DoD/OFOISR for public release under 06-S-0389 on 12 December 2005