Sirific Wireless Corporation

Javad Khajehpour

Tajinder Manku

The present invention relates generally to amplifiers, and more specifically to multi-band and/or multi-standard low noise amplifiers. There are currently no inexpensive, highperformance, fully-integrable, multi-standard low noise amplifiers (LNAs) available. The invention provides a suitable LNA for a multi-band and/or multi-standard receiver in wireless and other applications. This LNA comprises a positive signal amplifier having a first input for receiving a positive RF signal, and a first output for providing an amplified positive RF signal; a negative signal amplifier having a second input for receiving a negative RF signal, and a second output for providing an amplified negative RF signal; and a tunable differential filter having a tuning control input, a third input for said first output and a fourth input for said second output; the frequency response of said tunable differential filter varying with a control signal input to said tuning control input, whereby signal of undesired frequencies may be filtered from said first output and said second output.

Multi-standard amplifier

The invention is implemented in the form of modifications to a Gilbert mixer circuit. The modifications alleviate disadvantages and problems introduced because of low voltage power supply typically found in low-power devices such as portable cellular phones. In addition to improving the linearity performance, the new design also provides good matching between I and Q signals, and decreases the switching noise in the active mixer by reducing the switching current. The invention can be applied to both single stage and dual mixers to give low noise performance and Automatic Gain Control (AGC).

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Waterloo, Canada

Javad Khajehpour