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Subharmonic Quadrature Sampling Receiver and Design

In modern wireless communication systems, the receiver is to recover with high sensitivity and accuracy baseband signal data or messages, which have been transmitted or broadcasted by way of modulation on a radio frequency (RF) carrier. However, these conventional high frequency receivers comprise a large number of discrete components for RF signal processing. These components often introduce parasitics and other unknowns which are much less repeatable and predictable than circuits made from the integrated circuit (IC) process. Finding an IC technology with the right balance of cost and performance is not an easy compromise.

The invention provides a quadrature demodulation receiver for narrow-band communication systems comprising means for directly sampling an incoming signal. It is modulated on a radio-frequency carrier at a sampling frequency, which can be substantially lower than the carrier frequency to demodulate said signal into its in-phase and quadrature components. The novel technique permits the circuit to function across a wide range of frequencies with a high-degree of precision. This can be applied to a wide range of applications including RF signal downconversion for image rejection, direct conversion receivers, and clock recovery in communications circuits.

The new invention avoids the individual trimming and tuning of discrete components required to make up for the parasitic and other unknown effects in conventional wireless communication systems. It also resolves problems with monolithic integration of a high speed digital receiver which means that high-speed, low-noise, small-signal, front-end circuitries and high-density, low-power analogue, digital baseband processing circuitries must be put close together.
Technology Benefits
1. It is a precise, compact and simple method to offer very low-powe r potential in circuit implementation compared with existing methods
2. It uses a signal at a non-harmonic frequency of the RF to generate I and Q sampling signals for subsampling, and it is a novel method
3. It can generate picosecond-precise sampling of the I/Q components of a RF signal
Technology Application
- RF signal downconversion for image rejection, direct conversion receivers
- Clock recovery in communications circuits
Supplementary Information
Patent Number: US5937013A
Application Number: US1997778676A
Inventor: Lam, Marcos Chun Wing | Ling, Curtis Chih Shan
Priority Date: 3 Jan 1997
Priority Number: US5937013A
Application Date: 3 Jan 1997
Publication Date: 10 Aug 1999
IPC Current: H03D000300 | H04L0027227 | H04L002700
US Class: 375340 | 375376
Assignee Applicant: The Hong Kong University of Science & Technology
Title: Subharmonic quadrature sampling receiver and design
Usefulness: Subharmonic quadrature sampling receiver and design
Summary: For narrow-band communication system.
Novelty: Quadrature demodulation high-speed receiver for narrow-band communication system
Sub Category
Application Date
3 Jan 1997
Application No.
US 08/778676
Patent Information
US 5937013
ID No.
Hong Kong

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