الفهرس 
Abstract
NIRSOnly 14 pages are availabe for public view
 |  | from | 203 |  |  |
| | | from | 203 | | |
Abstract
Abstract The CMOS fabrication rapid growth has pushed the era to an everlasting technological evolution. Nowadays, new technologies have arouse in many major fields like communication, transportation and most important bio-medical engineering and
health care. Near Infrared Spectroscopy (NIRS) and functional Near Infrared Spectroscopy (fNIRS) has proved to be an excellent technique for detecting and diagnose
many diseases by a non invasive and safe method specially when combined with other
techniques like functional MRI (fMRI). One of the major design considerations of an
NIRS optical receiver is the input referred noise which greatly depends on the Transimpedance amplifier (TIA). In this regards, this thesis will focus on the design of
the analog front end TIA for the frequency domain NIRS (FD-NIRS) optical receiver
and explores a new TIA topologies.
The first proposed TIA is a regulated inverter cascode TIA (RIC-TIA). The design
introduces a two regulating amplifiers which regulates the cascode transistors. Accordingly, a higher effective transconductance is obtained due to the regulation effect
resulting in a higher gain bandwidth product (GBW) compared to the conventional
inverter cascode TIA. This proposed RIC-TIA is optimized for a 2 pF, off-chip photodiode. The post layout simulation results shows a great enhancement over the
inverter cascode specially in the sensitivity and input noise parts.
The second proposed TIA is a current reuse with regulated cascode topology (CR-
1RGC-TIA). The regulation of the cascode transistor also serves to increase the effective transconductance of the TIA and enhances the GBW at a slight increase of the
power consumption compared to the ordinary current reuse TIA (CR-TIA).
The third proposed TIA, the (RGC-InvCas-TIA), is a combination between the regulated cascode TIA (RGC-TIA) and the inverter cascode TIA (InvCas-TIA). The
topology benefits from the low input impedance realized by the RGC input stage and
the high transimpedance gain attained by the InvCas output stage. Consequently,
better performance can be obtained compared to the RGC-TIA and the InvCas-TIA.
Moreover, the isolation of the input capacitance that is achieved by the low input
impedance of the RGC-TIA stage greatly separated the BW determination from the
transimpedance gain determination. Thus, the trade-off between the gain and the
BW is greatly reduced.
Moreover, three complete analog receiver front ends are introduced and optimized for
the FD-NIRS with a two of the proposed TIAs being used as a pre-amplifier. The first
receiver uses the CR-RGC-TIA as the a front end amplifier and the other receivers
uses the RIC-TIA at the front end. All receivers include an automatic gain control
(AGC) circuitry to increase the maximum overloading input current which enhances
the dynamic range. An implementation of the third receiver is introduced and the
measurement results are discussed.
Finally, a discrete components, hardware implementation of an NIRS analog transceiver
and a pulse oximeter device is presented. The presented NIRS device can produce an
approximate 2 V difference between the deep and no respiration states when applied
to the human forehead. For the implemented pulse oximeter, the device can extract the Photoplethysmography (PPG) signal from the person finger tip which is used to determine the pulse rate and the tissue oxygenation.