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Stepped gain mixer

A mixer, step-by-step technology, applied in the modulation conversion, electrical components, demodulation and other directions of semiconductor devices with at least two electrodes, which can solve problems such as data throughput imposition

Active Publication Date: 2013-09-18
QUALCOMM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The signal-to-noise ratio imposes a rough limit on the data throughput that a communication system can transmit

Method used

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  • Stepped gain mixer
  • Stepped gain mixer
  • Stepped gain mixer

Examples

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Embodiment Construction

[0028] Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings.

[0029] figure 1 is a simplified block diagram of a receiver 10 that performs IQ demodulation for an Orthogonal Frequency Division Multiplexing (OFDM) based wireless communication system. In one embodiment, the functions of the receiver 10 are performed by a radio frequency (RF) transceiver integrated circuit (IC) 11 and a digital baseband IC 12 . The RF transceiver IC 11 is called a "transceiver" because it includes a transmitter as well as a receiver. The circuit that performs the transmit function of the RF transceiver IC 11 is in figure 1 Not shown in . Receiver 10 uses an amplified stepped gain mixer section 15 to provide a signal-to-noise ratio higher than that achievable by conventional mixers. The higher signal-to-noise ratio is achieved in part by providing a larger gain control range. The signal-to-noise ratio of the receiver 10 tr...

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PUM

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Abstract

An amplified stepped gain mixer portion improves the signal-to-noise ratio of a receiver by using multiple gain states to improve linearity. The mixer portion includes an amplifier, a switch and two transistors. The amplifier output is coupled to the sources of the two transistors. An oscillating signal is present on the transistor gates. The transistor drains are coupled to one another through the switch when the switch is closed. The mixer portion operates in two modes. In a 1 / 2 mode, the mixer portion output current flows only through the first transistor and not through the second transistor because the switch is open. In a 2 / 2 mode, the mixer portion output current flows through both transistors. The mixer portion is configured such that the switch is closed when a switching signal is asserted. The switching signal is asserted when a bit of a mixer control register is written to.

Description

technical field [0001] The present invention relates generally to wireless communication devices, and more particularly to a mixer providing stepped gain control in a receiver front end. Background technique [0002] Receivers for wireless communication systems typically require a low noise amplifier (LNA) followed by a double-balanced mixer to pre-amplify incoming signals and down-convert those signals to the appropriate intermediate frequency (IF) or baseband frequency. A typical receiver has a signal-to-noise ratio (SNR) of no more than about 20 dB. The signal-to-noise ratio imposes a rough limit on the data throughput that a communication system can transmit. For example, a system following the IEEE 802.11g standard with a signal-to-noise ratio of about 20 dB cannot transmit much more than about 25 MB / sec of data. Newer wireless communication systems based on Orthogonal Frequency Division Multiplexing (OFDM) are being developed and allow transmission of higher data rat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03D7/14H03D7/12
CPCH03D7/1466H03D7/1458H03D7/1491H03D2200/0025H03D7/165H03D7/1441H03D7/125H03D7/14H03D7/12
Inventor 王新威张向东
Owner QUALCOMM INC