Agency for Science, Technology and Research

Seagate Technology Incorporated

Cyrips Pte Ltd.

Sheng Jau Wong

Yuanjin Zheng

Yong Ping Xu

Myint Ngwe

Kah Liang Gan

Eng Hock Lim

Aruna B Ajjikuttira

Pradeep Basappa Khannur

Victor WengKhin Chew

Chin Boon Tear

Bernard Tuang Liang Lim

Jia Jun Zheng

An RFID transceiver () includes a common frequency source (), a receiving channel () and a transmitting channel (). The common frequency source () is configured to provide a predefined intermediate frequency signal f, and a predefined carrier frequency signal f. The RFID receiving channel () includes an upconverting mixer () having a first input coupled to receive the predefined intermediate frequency signal f, a second input coupled to receive the predefined carrier frequency signal f, and an output, the upconverting mixer () operable to produce an upconverted signal at a frequency defined by f&#xb1;f. The RFID receiving channel () further includes an image rejection downconverting mixer () having a first input coupled to receive an RFID signal having a carrier frequency substantially at the predefined carrier frequency f, a second input coupled to receive the upconverted signal, and an output, the image rejection downconverting mixer () operable to produce an output a downconverted signal at substantially the predefined intermediate frequency f. The RFID transmitting channel () includes a modulator () operable to modulate modulation data onto the predefined carrier frequency signal f.

Architecture for RFID tag reader/writer

A notch filter with a high Q factor, which is integrated with a first and a second cascoded LNA, is totally contained on an integrated chip. The notch filter, comprising two Q-enhancement circuits, is coupled to the second differential LNA. The two Q-enhancement circuits are combined to generate sufficient negative impedance to compensate for the loss in the on-chip low Q inductors. To improve the image rejection of the notch filter in a wide frequency band, the notch filter uses an automatic current tuning circuit which consists of an analog multiplier and fixed and voltage controlled current sources. Furthermore, by modifying the connection and location of the tunable varactor, another wideband tunable notch filter is implemented. The notch filter can be applied in all current wireless receiver systems.

Wideband monolithic tunable high-Q notch filter for image rejection in RF application

A DCR RF front-end removes the DC term resulting from mixer port to port leakage and feeds RF and LO signals into the mixers with different phase combinations. The signal inputs to the mixers result in the intermediate frequency (IF) output of mixers being 180 degrees out of phase and their DC terms in phase. When subtracting the two outputs from each other the IF signals add up while the DC terms cancel giving a DC free output. A DC offset feedback tuning loop detects the DC offset in the IF domain and then feeds back the tuning voltage to current injection mixers. A multiplier cancels the IF signals and amplifies the DC offset and a comparator compares the amplified DC offset with a threshold voltage and controls the gain of current injection mixers. The feedback tuning loop thus tracks time-varying DC offsets in real-time.

DC offset-free RF front-end circuits and systems for direct conversion receivers

A method of manufacturing disc drives. Before a pivot cartridge is assembled into a disc drive, impedance readings of the pivot cartridge are taken, preferably, at more than one rotational position and across a frequency range. The pivot cartridge is accepted for assembly into the disc drive only if its impedance readings compare favorably with readings taken of a good pivot cartridge. Otherwise, the pivot cartridge is rejected and the impedance readings are analyzed to provide identification of the defect in the pivot cartridge. In addition, a system and a storage device readable by a computer system for implementing the method of screening pivot cartridges and identifying causes of defects is provided.

Cartridge screening method with pin-point capabilities on the causes of defects

Growing community of inventors

Johor Bahru, Malaysia

Sheng Jau Wong