By Topic

A Solution to the Second Harmonic Interference in Acoustically Coupled Data Sets

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

1 Author(s)
Meidan, R. ; Applied Digital Data Systems, Inc., NY

The difficulties encountered by acoustically coupled 103 compatible data sets are considered. In particular the limitations introduced by the harmonic distortion generated by the nonlinearity of the telephone's microphone are analyzed. It is shown that interference between the second harmonic of the transmitted signal and the received signal restricts the application of acoustic coupling to lines of relatively low attenuation. A method of cancelling the second harmonic by adding a third harmonic component to the transmitted signal is described, and shown to be independent of the microphone's nonlinearities. The effect of handset placement on the microphone's performance is also analyzed and experimental results are given. Incorporating the described method of reducing second harmonic distortion and choosing the optimal handset placement allow Applied Digital Data Systems acoustic coupler to transmit at full power and to communicate reliably in full duplex on lines of up to 30-dB attenuation.

Published in:

Communication Technology, IEEE Transactions on  (Volume:19 ,  Issue: 2 )