A wireless biotelemetry system operates in vivo, which requires low power consumption for long-lasting operation, high output power for long transferable distance, and high throughput for incorporating many recording electrodes and transmitting raw brain signals. An implantable 2.4-GHz on-off keying (OOK) transmitter with high throughput and high energy efficiency for wireless biotelemetry systems has been designed in a 0.18-μm CMOS process. To balance power consumption and output power, a complementary voltage-controlled oscillator for the proposed transmitter is employed. Power consumption of the transmitter is reduced by switching the oscillator on and off to generate an OOK modulated signal. The transient delay for the transmitter is derived and applied to implement a high throughput transmitter. Rat skin-mimic emulating the implant environment such as electrical properties of the skin is used to measure the proposed transmitter in vitro. To transmit 136 Mb/s of OOK data, the transmitter consumes 3 mW of dc power and generates an output power of -14 dBm. The transmitter achieves energy efficiency of 22 pJ/bit with an associated bit error rate of 1.7 × 10- 3 without using an error correction scheme.
[Show abstract][Hide abstract] ABSTRACT: This paper presents a novel CMOS wireless temperature sensor design in order to improve the sensitivity and linearity of our previous work on such devices. Based on the principle of CMOS double zero temperature coefficient (DZTC) points, a combined device is first created at the chip level with two voltage references, one current reference, and one temperature sensor. It was successfully fabricated using the 0.35 μm CMOS process. According to the chip results in a wide temperature range from -20 °C to 120 °C, two voltage references can provide temperature-stable outputs of 823 mV and 1,265 mV with maximum deviations of 0.2 mV and 8.9 mV, respectively. The result for the current reference gives a measurement of 23.5 μA, with a maximum deviation of 1.2 μA. The measurements also show that the wireless temperature sensor has good sensitivity of 9.55 mV/°C and high linearity of 97%. The proposed temperature sensor has 4.15-times better sensitivity than the previous design. Moreover, to facilitate temperature data collection, standard wireless data transmission is chosen; therefore, an 8-bit successive-approximation-register (SAR) analog-to-digital converter (ADC) and a 433 MHz wireless transmitter are also integrated in this chip. Sensing data from different places can be collected remotely avoiding the need for complex wire lines.
[Show abstract][Hide abstract] ABSTRACT: LFM signal is used in underwater signal processing commonly. When there are multi-number objects, the received signal always is multi-frequency LFM signal. Based on short-time Fourier transform and fractional Fourier transform, the short-time fractional Fourier transform is used to process the multi-frequency LFM signal. For the arbitrary LFM signal component, it can get a impulse function in the fractional domain, when choosing the relevant rotation angle. As for other components, the energy is concentrated in a range of frequency at this rotation angle. Therefore, the short-time fractional Fourier transform has best energy collection for the LFM signal. The simulation and test result show that the short-time fractional Fourier transform is valid when processing the multi-frequency LFM signal.
Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC), 2011; 01/2011
[Show abstract][Hide abstract] ABSTRACT: A 2.4-GHz CMOS on-off keying (OOK) transmitter is developed for applications that require high data rate over 10Mbps in the area of wireless body area network (WBAN) and medical implant communication service (MICS). A novel analog pulse-shaping circuit for reducing power consumption and circuit complexity is employed for the OOK transmitter. Fabricated in 0.13 mu m CMOS, the transmitter core excluding the 50 ohm driving buffer dissipates 0.95mWfrom 1.2-V supply. Measurement shows that it can support the data rate up to 22 Mbps. With the pulse-shaping capability enabled, the transmitter output spectrum shows successful suppression of the sidelobe power below -42 dBc at 100MHz offset from the center frequency.
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