Low Bit Rate Voiceband Encoders/Decoder
Semiconductor
February 1999
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HC-55564
Continuously Variable
Slope Delta-Modulator (CVSD)
Features
• All Digital
• Requires Few External Parts
• Low Power Drain: 1.5mW Typical From Single 4.5V
To 6V Supply
• Time Constants Determined by Clock Frequency;
No Calibration or Drift Problems: Automatic Offset
Adjustment
• Half Duplex Operation Under Digital Control
• Filter Reset Under Digital Control
• Automatic Overload Recovery
• Automatic “Quiet” Pattern Generation
• AGC Control Signal Available
Description
The HC-55564 is a half duplex modulator/demodulator CMOS
intergrated circuit used to convert voice signals into serial NRZ
digital data and to reconvert that data into voice. The conver-
sion is by delta-modulation, using the Continuously Variable
Slope (CVSD) method of modulation/demodulation.
While the signals are compatible with other CVSD circuits, the inter-
nal design is unique. The analog loop filters have been replaced by
very low power digital filters which require no external timing compo-
nents. This approach allows inclusion of many desirable features
which would be difficult to implement using other approaches.
The fundamental advantages of delta-modulation, along with its
simplicity and serial data format, provide an efficient (low data
rate/low memory requirements) method for voice digitization.
The HC-55564 is usable from 9kbits/s to above 64kbps. See the
Harris Military databook for a MIL-STD-883C compliant CVSD.
Application Note 607.
[ /Title
(HC-
55564
)
/Sub-
ject
(Con-
tinu-
ously
Vari-
able
Slope
Delta-
Modu-
lator
(CVS
D))
/
Autho
r ()
/Key-
words
(Har-
ris
Semi-
con-
ductor
, Tele-
com,
SLICs
,
SLAC
s,
Tele-
phone,
Tele-
phony,
Applications
• Voice Transmission Over Data Channels (Modems)
• Voice/Data Multiplexing (Pair Gain)
• Voice Encryption/Scrambling
• Voicemail
• Audio Manipulations: Delay Lines, Time Compression,
Echo Generation/Suppression, Special Effects, etc.
• Pagers/Satellites
• Data Acquisition Systems
• Voice I/O for Digital Systems and Speech Synthesis
Requiring Small Size, Low Weight, and Ease of
Reprogrammability
• Related Literature
- AN607, Delta Modulation for Voice Transmission
Ordering Information
PART
NUMBER
HC1-55564-2
HC1-55564-5
HC1-55564-9
HC3-55564-5
HC9P55564-5
TEMP.
RANGE (
o
C)
-55 to 125
0 to 75
-40 to 85
0 to 75
0 to 75
PACKAGE
14 Ld CERDIP
14 Ld CERDIP
14 Ld CERDIP
14 Ld PDIP
PKG. NO.
F14.3
F14.3
F14.3
E14.3
16 Ld Plastic SOIC (W) M16.3
Pinouts
HC-55564
(PDIP, CERDIP)
TOP VIEW
HC-55564
(SOIC)
TOP VIEW
V
DD
1
14 DIG OUT
13 FZ
12 DIG IN
11 APT
10 ENC/DEC
9 CLOCK
8 DIG GND
V
DD
1
16 DIG OUT
15 FZ
14 DIG IN
13 APT
12 ENC/DEC
11 CLOCK
10 DIG GND
9 NC
ANALOG GND 2
A
OUT
3
ANALOG GND 2
A
OUT
3
AGC 4
AIN 5
NC 6
NC 7
NC 8
AGC 4
A
IN
5
NC 6
NC 7
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright
©
Harris Corporation 1999
File Number
2889.5
1
HARRIS [ HARRIS CORPORATION ]
