An ASK demodulator for data telemetry in biomedical application.

Area of Science:

• Biomedical Engineering
• Integrated Circuit Design
• Wireless Communication

Background:

• Wireless telemetry systems are crucial for remote patient monitoring and implantable medical devices.
• Amplitude Shift Keying (ASK) is a common modulation technique for low-power wireless biomedical applications.
• Efficient demodulator design is essential for reliable data recovery in low-power biomedical telemetry.

Purpose of the Study:

• To present a novel demodulator design for Amplitude Shift Keying (ASK) based wireless telemetry systems.
• To achieve a high data rate of up to 300 Kbits per second (bps) for biomedical applications.
• To enable detection of low modulation indexes (≥1%) for improved signal sensitivity.

Main Methods:

• The demodulator incorporates a single-to-differential Operational Transconductance Amplifier (OTA), a current-mode full-wave rectifier, a log-domain peak detector, a variable-gain amplifier, and a comparator.
• Tunable rising and falling time constants are implemented using off-chip components to accommodate various modulation indexes and data rates.
• Circuit blocks are designed and simulated using the Taiwan Semiconductor Manufacturing Company (TSMC) 0.18microm process.

Main Results:

• The designed demodulator supports data rates up to 300 Kbits per second (bps).
• It successfully detects envelopes with modulation indexes of 1% or greater.
• The circuit occupies a small area of 120x420 micrometers squared and consumes only 1mW of power at a 1.8V supply voltage.

Conclusions:

• The proposed demodulator design is suitable for low-power, high-data-rate wireless biomedical telemetry systems.
• The tunable nature of the design enhances its versatility for different biomedical sensing applications.
• The achieved performance metrics demonstrate the feasibility of the design for practical biomedical applications.