beautypg.com

8 doubletalktm carrier-in-carrier® (cnc), 9 regulatory compliance, 10 standard assemblies – Comtech EF Data CDM-750 User Manual

Page 39: 8 doubletalk, Carrier-in-carrier, Cnc)

background image

CDM-750 Advanced High-Speed Trunking Modem

Revision 2

Introduction

MN-CDM750

1–15

1.4.8

DoubleTalk

TM

Carrier-in-Carrier

®

(CnC)

Operating Mode

Requires the two carriers in a duplex circuit to share a common frequency. Different symbol rates are
allowed.

CnC Ratio

Ratio of Interferer Carrier Power to Desired Carrier Power (in dB). Positive values represent a stronger
Interferer Carrier, and negative values represent a stronger Desired Carrier. Range is +7 dB to -7 dB.

Symbol Rate Ratio

3:1 Tx/Rx or Rx/Tx

Inbound/Outbound frequency
uncertainty

±100kHz

Delay range

0 - 400 ms (230 - 290 ms factory default)

Es/No Degradation (dB)
measured at 0.0 dB CnC
Ratio

QPSK, 0.3 dB
8-PSK, 0.3 dB
16-APSK, 0.6 dB
32-APSK, 1.0 dB

Monitor Functions

• Delay, in milliseconds
• Frequency offset (between outbound interferer and desired inbound): 100 Hz resolution
• CnC ratio, in dB (ratio of absolute power, outbound interferer to desired inbound)

CnC Monitor Accuracy

± 1.0 dB for symmetric symbol rate

1.4.9

Regulatory Compliance

“CE” as follows:

EN 55022 Class A (Emissions)
EN 50082-1 (Immunity)
EN 60950 (Safety)

EN 61000-3-2
EN 61000-3-3
EN 61000-4-2
EN 61000-4-4
EN 61000-4-5

EN 61000-4-6
EN 61000-4-8
EN 61000-4-9
EN 61000-4-11
EN 61000-4-13

FCC

FCC Part 15 Subpart B

RoHS Compliance

Yes

1.4.10 Standard Assemblies

Assembly

Description

Where Installed

PL-0000571 Modem

Card

In chassis (top cover access)

PL-0000612

Main Card (includes Ethernet Interfaces)

PL-0000626

PIIC Motherboard Assembly

KT-0000150

AC Power Supply for modem (not BUC)