Agency for Science, Technology and Research

Nanyang Technological University

Institute of Microelectronics

Yuanjin Zheng

Sheng Jau Wong

Yong Ping Xu

Yuan Gao

Zhiming Chen

Shengxi Diao

Minkyu Je

Xin Liu

Chun Huat Heng

Dong Han

San Jeow Cheng

Kuang-Wei Cheng

Chin Boon Tear

Bin Zhao

Xiaohua Feng

Fei Gao

Foo Chung Choong

Myint Wai Phyu

A photo-acoustic sensing apparatus () for non-invasive measurement of blood parameters of a subject () comprises a photo-acoustic sensor () for sensing photo-acoustic signals () induced when a region of the subject is illuminated by a light source (). A first sensor processing module () may derive blood oxygen saturation using sensed photo-acoustic signals (). A second sensor processing module () may derive blood core temperature using sensed photo-acoustic signals. A third sensor processing module () may derive blood glucose using sensed photo-acoustic signals. The sensing apparatus is configured to derive at least one of: a de-correlated value () of blood oxygen saturation of the subject; a de-correlated value () of blood core temperature of the subject; and a de-correlated value () of blood glucose of the subject.

Photo-acoustic sensing apparatus and methods of operation thereof

According to embodiments of the present invention, a frequency shift keying transmitter is provided. The frequency shift keying transmitter includes a logic gate arrangement that produces an output signal having a frequency that depends on input signals to the logic gate arrangement, a clock generator coupled to the logic gate arrangement, the clock generator adapted to produce a clock signal, and a sampling arrangement coupled to the logic gate arrangement, the sampling arrangement adapted to receive a data signal, wherein the sampling arrangement is configured to sample the clock signal to generate periodic waveforms delayed from each other by an interval determined by the point the clock signal is sampled, wherein the sampling arrangement is configured to be controlled by the data signal to have the logic gate arrangement select periodic waveforms that are delayed from each other by one of a set of intervals associated with the data signal, to be used as the input signals to the logic gate arrangement to produce the output signal.

Frequency shift keying transmitter

A method and an apparatus for a duty-cycled injection locked oscillator is provided for frequency shift keyed (FSK) signal transmissions. The oscillator includes a resonance LC tank and a first switching device. The first switching device is coupled to the resonance LC tank and injects an initial current pulse with a predetermined pulse magnitude into the resonance LC tank. The initial current pulse also fixes an initial phase of the duty-cycled injection locked free-running oscillator in response to the predetermined magnitude of the initial current pulse to enable fast settling of injection locking and high data rate operation of the duty-cycled injection locked oscillator. The oscillator also includes a second switching device, such as a differential pair of switching devices. The second switching device is coupled to the LC resonance tank for injecting a gated periodic reference signal having a duty cycle modified to reduce power of the reference signal by approximately seventy-five per cent.

Method and apparatus for a duty-cycled harmonic injection locked oscillator

A phase shift keying transmitter circuit that includes: a variable frequency conversion stage adapted to receive a first data signal, wherein the variable frequency conversion stage comprises a plurality of frequency modulating elements, wherein the first data signal controls the number of the plurality of frequency modulating elements that are operated so as to control an operating frequency of the variable frequency conversion stage; and an output stage configured to switch between one of two possible outputs, the signals provided by one of the two possible outputs having an opposite polarity to the other, wherein the output stage is configured to receive a second data signal to control the switching between the two possible outputs, wherein the output stage is coupled to the variable frequency conversion stage and wherein the switching between the two possible outputs changes the phase of a signal from the variable frequency conversion stage by 180&#xb0;.

Phase shift keying transmitter circuit

Embodiments provide a gm-ratioed amplifier. The gm-ratioed amplifier comprises a first input voltage terminal and a second input voltage terminal, a first output voltage terminal and a second output voltage terminal, and an amplifying unit. The amplifying unit may be coupled between the input voltage terminals and the output voltage terminals and may be adapted to supply an output voltage to the output terminals in dependence on an input voltage supplied to the input terminals. The amplifying unit may comprise a gm-load, which comprises a first load branch comprising a first field effect transistor, and a second load branch comprising a second field effect transistor. A first source/drain terminal and a gate terminal of the first field effect transistor may be coupled to the first output voltage terminal, and a first source/drain terminal and a gate terminal of the second field effect transistor may be coupled to the second output voltage terminal. A second source/drain terminal of the first field effect transistor and a second source/drain terminal of the second field effect transistor may be coupled with each other through a first transistor arrangement such that a linearity of response of the output voltage to the input voltage is improved.

GM-ratioed amplifier

A transmitter with modulation comprising a phase changing stage having a first switch and a second switch coupled t the first switch, a first transistor and a second transistor individually coupled to the each switch. The transmitter is configured to receive a phase changing signal having a first state and a second state. The first switch is configured t operate in an opposing manner to the second switch such that only the first transistor is configured to be turned on i the first state and only the second transistor is configured to be turned on in the second state upon receipt of the phase changing signal by the switches so as to achieve a change in an output phase of the transmitter when the phase changing signal switches from the first state to the second state.

Ultra-wideband impulse radio transmitter with modulation

An electrocardiogram signal processing system is provided which includes: a wavelet transformation unit comprising a plurality of outputs, each output being connected to one of a plurality of scales, wherein the wavelet transformation unit is adapted to transform an input electrocardiogram signal into a set of wavelets, each wavelet being output to one of the scales; a plurality of signal processing blocks, each of the signal processing blocks coupled to a respective output of the wavelet transformation unit and configured to receive and process the wavelet from the respective output, wherein the signal processing blocks provide processing functions which differ from one another.

Electrocardiogram signal processing system

A modulator, a demodulator and a modulator-demodulator are provided. A modulator includes a first intermediate signal processing path adapted to route a first intermediate signal; a second intermediate signal processing path adapted to route a second intermediate signal; a first amplifier coupled into the first intermediate signal processing path; a second amplifier coupled into the second intermediate signal processing path; and a chopper circuit coupled into the first intermediate signal processing path; wherein the chopper circuit is adapted to process the first intermediate signal in dependence on first baseband data; wherein the first amplifier is adapted to amplify the first intermediate signal processed by the chopper circuit in dependence on second baseband data; and wherein the second amplifier is adapted to amplify the second intermediate signal in dependence on the second baseband data.

Modulator, demodulator and modulator-demodulator

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 feedback image rejection downconversion system is described, which can be used in low IF receivers with good performance and completely integrated. In the forward path of the system, quadrature mixers and complex filters are used for frequency downconversion and separation of the RF signal from the image signal. In the feedback path, a correlator, a gain mismatch estimator and two VGAs have been used to detect, estimate and compensate the amplitude and phase mismatch between the forward I and Q path signals. The whole system is self-tuned and can operate in both closed and open loop mode. A very high and robust image rejection ratio (over 60 dB) has been achieved.

Growing community of inventors

Singapore, Singapore

Yuanjin Zheng