SYNOPSIS
Dual-tone Multi-Frequency (DTMF) signaling is the basis for voice communications control and is widely used worldwide in modern telephony to dial numbers and configure switchboards. It is also used in systems such as in voice mail, electronic mail and telephone banking.
The detector part of early DTMF systems consisted of analog implemented bandpass filter banks, which were tuned to the eight standard frequencies. As analog lines as well as many other analog systems were converted to digital, researchers became ....etc

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This musical light alarm circuit is very simple, uses only 7 components, a LDR and a 3.6 V battery or 3 x 1.2 volts rechargeable batteries. The well-known UM66 is used as the sound generator and will give a pleasent wake up alarm.

As you probably know the LDR is a light dependent resistor. Normally the resistance of an LDR is very high, sometimes as high as 1M , but when they are illuminated with light resistance drops dramatically. In the circuit adjust the 220K preset to the desired sensitivity, meaning adjusting the threshold point wher ....etc

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advantages of multi tone siren

A siren is a loud noise making device. Civil defense sirens are mounted in fixed locations and used to warn of natural disasters or attacks. Sirens are used on emergency service vehicles such as ambulances, police cars and fire trucks. There are two general types: pneumatic and electronic.

Many fire sirens (used for calling the volunteer fire fighters) serve double duty as tornado or civil defense sirens, alerting an entire community of impending danger. Most fire sirens are either mounted on the roof of a fire ....etc

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i need this project description, working principle, circuit diagram and ppt ....etc

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Abstract
Two major objectives are concerned in this paper. On one hand, a multiplicity of typical methodologies available for achieving dual-frequency operation for microstrip patch antennas are summarized and classified into three categories, based on their intrinsic mechanisms. On the other hand, by employing the dual-frequency solutions, microstrip patch antennas are applied to the mobile handsets of the third-generation IMT-2000 system. Two novel microstrip patch antennas with broadband property and miniaturized size have been proposed a ....etc

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To get full information or details of Dual tone Multi Frequency DTMF please have a look on the pages

http://seminarsprojects.net/Thread-Dual-tone-Multi-Frequency-DTMF-signaling

http://seminarsprojects.net/Thread-Dual-tone-multi-frequency-signaling-DTMF?pid=79283#pid79283

if you again feel trouble on Dual tone Multi Frequency DTMF please reply in that page and ask specific fields in Dual tone Multi Frequency DTMF ....etc

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Remote device control using Radio Frequency

The project compares the communication of control signals using radio frequency
and Infra Red Rays. The STR is ideal for short-range remote control applications where
cost is a primary concern. The receiver module requires no external RF components
except for the antenna. It generates virtually no emissions, making FCC and ETSI
approvals easy. The super-regenerative design exhibits exceptional sensitivity at a very
low cost. A SAW filter can be added to the an ....etc

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Final Report on
Dual-Tone Multiple Frequency (DTMF) Detector Implementation
Presented By:
Giiner Arslan
for EE382C Embedded Software Systems
Abstract
Dual-tone Multi-frequency (DTMF) signals are used in touch-tone telephones as well as many other areas such as interactive control, telephone banking, and pager system. As analog telephone lines are converted to digital, researchers became interested in digital DTMF detectors.
There are many digital DTMF detecting algorithms, but most of them do not comply with ....etc

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plz tell us theory and application of tone generator control with light ....etc

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about multi device control system using frequency modulation in to the right box for getting free material and support from us/dedicated premium members..
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