IL34118DW Datasheet PDF - ETC
| Part Number | IL34118DW | |
| Description | Voice Switched Speakerphone Circuit | |
| Manufacturers | ETC | |
| Logo |  |
|
|
There is a preview and IL34118DW download ( pdf file ) link at the bottom of this page. Total 12 Pages | ||
Preview 1 page No Preview Available !
TECHNICAL DATA
Voice Switched Speakerphone Circuit
IL34118
The IL34118 Voice Switched Speakerphone Circuit incorporates
the necessary amplifiers, attenuators, level detectors, and control
algorithm to form the heart of a high quality hands-free speakerphone
system. Included are a microphone amplifier with adjustable gain and
MUTE control, Transmit and Receive attenuators which operate in a
complementary manner, level detectors at both input and output of
both attenuators, and background noise monitors for both the transmit
and receive channels. A Dial Tone Detector prevents the dial tone
from being attenuated by the Receive background noise monitor
circuit. Also included are two line driver amplifiers which can be used
to form a hybrid network in conjunction with an external coupling
transformer. A high pass filter can be used to filter out 60 Hz noise in
the reseive channel, or for other filtering functions. A Chip Disable
pin permits powering down the entire circuit to conserve power on
long loops where loop current is at a minimum.
The IL34118 may be operated from a power supply, or it can be
powered from the telephone line, requiring typically 5.0 mA. The
IL34118 can be interfaced directly to Tip and Ring (through a
coupling transformer) for stand-alone operation, or it can be used in
conjunction with a handset speech network and or other features of a
featurephone.
• Improved Attenuator Gain Range: 52 dB Between Transmit and
Receive
• Low Voltage Operation for Line-Powered Applications (3.0-
6.5 V)
• 4 Point Signal Sensing for Improved Sensitivity
• Background Noise Monitors for Both Transmit and Receive
Paths
• Microphone Amplifier Gain Set by External Resistors - Mute
Function Included
• Chip Disable for Active Standby Operation
• On Board Filter Pinned-Out for User Deined Function
• Dial Tone Detector to Inhibit Receive Idle Mode During Dial
Tone Presence
ORDERING INFORMATION
IL34118N Plastic
IL34118DW SOIC
TA = -25° to 70° C for all packages
PIN ASSIGNMENT
1
|
| |
 
IL34118
ATTENUATOR CONTROL BLOCK
The Attenuator Control Block has the seven
inputs described above:
- Tthe output of the comparator operated by RLO2
and TLO2 (microphone/speaker side) - designated
C1.
- The output of the comparator operated by RLO1
and TLO1 (Tip/Ring) side) - designated C2.
- The output of the transmit background noise
monitor - designated C3.
- The output of the receive background noise
monitor - designated C4.
- The volume control.
- The dial tone detector.
- The AGC circuit.
The single output of the Control Block controls
the two attenuators. The effect of C1-C4 is as
follows:
Inputs
Output
C1 C2 C3 C4
Mode
Tx Tx
1
X Transmit
Tx Rx
Y
Y Fast Idle
Rx Tx
Y
Y Fast Idle
Rx Rx
X
1
Receive
Tx Tx
0
X Slow Idle
Tx Rx
0
0 Slow Idle
Rx Tx
0
0 Slow Idle
Rx Rx
X
0 Slow Idle
X = Don’t Care; Y = C3 and C4 are not both 0
A definition of the above terms:
1) “Transmit” means the transmit attenuator is
fully on (+6.0 dB), and the receive attenuator is
at max. attenuation (-46 dB).
2) “Receive” means both attenuators are controlled
by the volume control. At max. volume, the
receive attenuator is fully on (6.0 dB), and the
transmit attenuator is at max. attenuation (-
46 dB).
3) “Fast Idle” means both transmit and receive
speech are present in approximately equal
levels. The attenuators are quickly switched
(30 ms) to idle until one speech level dominates
the other.
4) “Slow Idle” means speech has ceassed in both
transmit and receive path. The attenuators are
then slowly switched (1 second) to the idle
mode.
5) Switching to the full transmit or receive modes
from any other mode is at the fast rate (30 ms).
A summary of the truth table is as follows:
1) The circuit will switch to transmit if: a) both
transmit level detectors sense higher signal levels
relative to the respective receive level detectors
(TLI1 versus RLI1, TLI2 versus RLI2), and b) the
transmit background noise monitor indicates the
presence of speech.
2) The circuit will switch to receive if: a) both
receive level detectors sense higher signal levels
relative to the respective transmit level detectors, and
b) the receive background noise monitor indicates the
presence of speech.
3) The circuit will switch to the fast idle mode if
the level detectors disagree on the relative strengths
of the signal levels, and at least one of the
background noise monitors indicates speech. For
example, refferring to the Expanded Logic Diagram
(Figure 8), if there is sufficient signal at the
microphone amp output (TLI2) to override the
speaker signal (RLI2), and there is sufficient signal at
the receive input (RLI1) to override the signal at the
hybrid output (TLI1), and either or both background
monitors indicate speech, then the circuit will be in
the fast idle mode. Two conditions which can cause
the fast idle mode to occur are a) when both talkers
are attempting to gain control of the system by talking
at the same time, and b) when one talker is in a very
noisy environment, forcing the other talker to
continually override that noise level. In general, the
fast idle mode will occur infrequently.
4) The circuit will switch to the slow idle mode
when a) both talkers are quiet (no speech present), or
b) when one talker’s speech level is continuously
overriden by noise at the other speaker’s location.
The time required to switch the circuit between
transmit, receive, fast idle and slow idle is determined
in part by the components at the CT pin (Pin 14). A
schematic of the CT circuitry is shown in Figure 4 and
operates as follows:
- RT is typically 120 kΩ, and CT typically 5.0 µF.
- To switch to the receive mode, I1 is turned on (I2
is off), charging the external capacitor to
+240 mV above VB. (An internal clamp prevents
further charging of the capacitor.)
- To switch to the transmit mode, I2 is turned on (I1
is off) bringing down the voltage on the capacitor
to -240 mV with respect to VB.
- To switch to idle quickly (fast idle), the current
sources are turned off, and the internal 2.0 kΩ
resistor is switched in, discharging the capacitor
to VB with a time constant = 2.0 KΩ x CT.
- To switch to idle slowly (slow idle), the current
sources are turned off, the switch at the 2.0 kΩ
resistor is open, and the capacitor discharges to
VB through the external resistor RT with a time
constant = RT x CT.
5
Preview 5 Page |
Part DetailsOn this page, you can learn information such as the schematic, equivalent, pinout, replacement, circuit, and manual for IL34118DW electronic component. |
| Information | Total 12 Pages | |
| Link URL | [ Copy URL to Clipboard ] | |
| Download | [ IL34118DW.PDF Datasheet ] | |
Share Link :
Electronic Components Distributor
|
An electronic components distributor is a company that sources, stocks, and sells electronic components to manufacturers, engineers, and hobbyists. |
| SparkFun Electronics | Allied Electronics | DigiKey Electronics | Arrow Electronics |
| Mouser Electronics | Adafruit | Newark | Chip One Stop |
Featured Datasheets
| Part Number | Description | MFRS |
| IL34118DW | The function is Voice Switched Speakerphone Circuit. ETC | |
Semiconductors commonly used in industry:
1N4148 |
BAW56 |
1N5400 |
NE555 | | ||
Quick jump to:
IL34
1N4
2N2
2SA
2SC
74H
BC
HCF
IRF
KA | ||