VLSI

VLSI stands for “very large scale integration”. This is the field which involves packing more and more logic devices into smaller and smaller areas. Thanks to VLSI, circuits that would have taken boardfuls of space can now be put into a small space few millimeters across. Digital VLSI circuits are predominantly CMOS based. Most of the VLSI circuits available in the commercial market nowadays are of the programmable type and are called programmable Logic Device is a whose logic characteristic can be changed and manipulated or stored through programming . The type of PLD is as follows:

· Programmable array logic (PAL)

· Configurable programmable logic devices (CPLD)

· Field programmable gate array ( FPGA)

Adaptive Noise cancelling is a speech-specific filtering technique to suppress additive interference. It is a sensible choice for speech-orientated devices in situations where the designer has no knowledge of the properties of interference that could potentially corrupt the input speech to a point beyond intelligibility. A good example of devices subject to such noise is mobile telephones, where the user may be communicating in a variety of environments. However, constraints appear when implementing a noise-cancelling algorithm on such a portable device, and issues of power consumption and silicon area become prominent