Adaptive duplexing eliminates the need for multiple switched duplexers in multiband systems. The technique is based on combining a low isolation device and an active double loop cancelling scheme. A duplexer provides attenuation to the main Tx signals entering the receiver and Tx noise corrupting the receiver band. The solution is tested on a direct conversion receiver and uses an adaptive oned...

The basic principle of feedforward noise cancellation for broadband active noise reduction is based on the availability of a reliable measurement of the noise source. Reliability is compromised in case the noise measurement is acoustically coupled to the actual active noise cancellation (ANC), as stability and performance of the feedforward compensation becomes ambiguous. This paper presents a ...

An integrated acoustic echo and noise cancellation system for hands-free telephony is presented. The proposed system includes a new residual echo cancellation scheme based on spectral analysis and a new double-talk detector suitable for real-time implementation. Residual echo is whitened via AR analysis during no near-end-talk period and is cancelled by noise reduction. Removing speech characte...

A noise reduction input matching technique for broadband low noise amplifiers (LNAs) is presented. The proposed LNA employs a positive active feedback network besides of the conventional common-gate (CG) amplifier to achieve both wideband input signal matching and low noise figure (NF), simultaneously. Compared to the conventional broadband noise cancellation techniques, the presented approach ...

Several easily implemented devices for doing ultrasensitive optical measurements with noisy lasers are presented. They are all-electronic noise cancellation circuits that largely eliminate excess laser intensity noise as a source of measurement error and are widely applicable. Shot-noise-limited optical measurements can now easily be made at baseband with noisy lasers. These circuits are especi...