Hearing Double: When Network Echo Cancellation is the Answer

by | Sep 16, 2014 | Software

Nothing can put a damper on a business call quite like an echo can.

With the workplace becoming increasingly global, the ability to get things done across the miles is more important than ever. But whether or not you conduct business across continents or just across town, telephone echo can be a hindrance to clear and efficient communication.

Network Echo cancellation is used to pinpoint and eliminate echo rapidly, the essential purpose being to mitigate any loss in vocal quality associated with the echo.

Echo is caused by discrepancies and imperfections in telephone wiring circuits. In a nutshell, most public telephone systems use dual-wire connections that carry vocal signals both ways. In the case of a phone company’s headquarters or private-branch exchange, those two and four wire configurations are converted with hybrid circuits. It’s these circuits that typically result in that pesky, and oftentimes maddening, echo.

What NetworkEcho Cancellation Does

The benefits of network echo cancellation are many, not the least of which is the ability to conduct business, or simply enjoy a telephone conversation.

Effective network echo cancellation takes place under an array of circumstances, including conversation segments during which participants speak simultaneously, as well as during conversations potentially hindered by invasive environmental noise. Successful network echo cancellation also gets the job done without interfering with signaling tones, as well as with transmissions from fax machines and modems.

How Network Echo Cancellation Works

Explained simply, network echo cancellation is designed to eliminate echo from audio signals with the use of a specific algorithm. By observing the transmitted signal and returned echo, the echo canceller can use estimates of the delayed and transmitted signals to remove the echo.

The estimated delayed and transmitted signals are essentially subtracted from the returned echo signal so quickly that you’d never know it – which is the point, after all. The delicate aspect of cancellation lies with the scaling of the original signal to precisely the point required to eliminate the echo without damaging anything else. The strategy employed in figuring out how best to scale is what sets algorithms apart.

Fairly flexible in terms of implementation, network echo cancellation algorithms can be established within both software and hardware. If you choose to take the software-based route, it’s worth noting that computational juice must be pulled from the central processing unit, or CPU, to operate the algorithm. This is especially important to consider if you anticipate that the system will be required to accommodate a significant number of simultaneous calls.

On the other hand, echo cancellationconducted with the use of hardware is ideal for phone systems that offer limited power from the CPU, or will be required to process a large quantity of simultaneous calls.

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