MT8840 Datasheet, PDF (1/8 Pages) Mitel Networks Corporation – ISO2-CMOS Data Over Voice Modem

ISO²-CMOS MT8840
®
Data Over Voice Modem
Features
• Performs ASK (amplitude shift keyed)
modulation and demodulation
• 32 kHz carrier frequency
• Up to 2 kbit/s full duplex data transfer rate
• On-chip oscillator
• On-chip tone caller for alerting functions
• Adjustable tone caller frequencies
• Selectable self-loop test mode
• 5V/2.5mA power supply
• ISO²-CMOS and switched capacitor
technologies
• 18 Pin DIP
Applications
• Simultaneous data and voice communication in
PABXs
• 2 kbit/s data modem
• "Smart" telephone sets
ISSUE 4
November 1990
Ordering Information
MT8840AE 18 Pin Plastic DIP
MT8840AS 18 Pin SOIC
0°C to +85°C
Description
The MT8840 is a carrier over voice modem which
allows simultaneous transfer of voice and data over
a single pair of wires. Data is transferred on an
amplitude shift keyed (ASK) 32 kHz carrier. On-chip
filters remove voice frequency signals from the
received composite voice and data signal prior to
demodulation. The modulating signal is a bit stream
with a typical data rate of 2 kbit/s. In addition, the
device contains a two tone warbler which functions
as a telephone ringer. The device is fabricated in
MITEL’s double-poly ISO²-CMOS technology
utilizing switched-capacitor techniques.
OSC1
OSC2
CK32
ETC MTC FATC
TxDI
RxDO
Timing
and
Control
Tone
Caller
Modulator
TX Bandpass
Filter
TX Post-
R
Filter
O
U
T
I
Demodulator
AGC
RX Bandpass
RX Pre-
N
Filter
Filter
G
TCO
TxO
RxE
RxI
DET
CRx
V_DD
V_SS
V_Ref
LOOP
Figure 1 - Functional Block Diagram
5-3