CML Semiconductor Products
PRODUCT INFORMATION
FX631
Features
Detects 12kHz and 16kHz SPM
Frequencies
Low Po
Low Power (3.0 Volt
MIN
<1.0mA)
Operation
Speechband
High Speechband Rejection
Proper
operties
Properties
Low-Voltage SPM Detector
Low-Voltag
w-Volta
Publication D/631/8 July 1998
one-Follower
Pac
acket
Tone-Follower and Packet Mode
Outputs
Applications
Complex
Complex and/or Simple
Telephone Systems
Call-Charge/-Logging
Call-Charge/-Logging
Systems
XTAL/CLOCK
XTAL/CLOCK
OSCILLATOR
XTAL
CLOCK
OUT
CLOCK IN
CLOCK
DIVIDERS
SYSTEM
V
SS
V
DD
TONE FOLLOWER
OUTPUT
SYSTEM
(12kHz/16kHz)
TONE
FOLLOWER
LOGIC
INPUT AMP
12kHz/16kHz
FX631
SIGNAL
IN (+)
AMP OUT
V
BIAS
Fig.1 Functional Block Diagram
Brief Description
The FX631 is a low-power, system-selectable
Subscriber Pulse Metering (SPM) detector to indicate
the presence, on a telephone line, of both 12kHz and
16kHz telephone call-charge frequencies.
Deriving its input directly from the telephone line,
input amplitude/sensitivities are component adjustable to
the user's national ‘Must/Must-Not Decode’
specifications via an on-chip input amplifier, whilst the
12kHz and 16kHz frequency limits are accurately
defined by the use of an external 3.579545MHz
telephone-system Xtal or clock-pulse input.
The FX631, which demonstrates high 12kHz and
16kHz performance in the presence of both voice and
noise, can operate from either a single or differential
analogue signal input from which it will produce two
individual logic outputs.
1
+
-
SIGNAL
IN (-)
32
1
LEVEL DETECTOR
DIVIDER
PERIOD
MEASURE
PACKET MODE
OUTPUT
PACKET
TONE
LOGIC
+20dB
SYSTEM
1. Tone Follower Output - A 'tone-following' logic
output producing a “Low” level for the period of a
correct decode and a “High” level for a bad
decode or N
OTONE
.
2. Packet (Cumulative Tone) Mode Output - To
respond and de-respond after a cumulative 40ms
of good tone (or N
OTONE
) in any 48ms period.
This process will ignore small fluctuations or
fades of a valid frequency input and is available
for µProcessor ‘Wake-Up’, Minimum tone
detection, N
OTONE
indication or transient
avoidance.
This system (12kHz/16kHz) selectable microcircuit,
which may be line-powered, is available in 16-pin plastic
DIL and surface mount SOIC and 24-pin plastic SSOP
packages.
CMLMICRO [ CML MICROCIRCUITS ]
