Biomedical Signal Analysis Lecture Notes PDF

Biomedical signal analysis  The human–instrument system: Some of the components of a human–instrument system are the following: 1. The subject or patient: It is important always to bear in mind that the main purpose of biomedical instrumentation and signal analysis...

Biomedical signal analysis  The human–instrument system: Some of the components of a human–instrument system are the following: 1. The subject or patient: It is important always to bear in mind that the main purpose of biomedical instrumentation and signal analysis is to provide a certain benefit to the subject or patient. All systems and procedures should be designed so as not to cause undue inconvenience to the subject and not to cause any harm or danger. In applying invasive or risky procedures, it is extremely important to perform a risk–benefit analysis and determine if the 2. Stimulus or procedure of activity: Application of stimuli to the subject in active procedures requires instruments such as strobe light generators, sound generators, and electrical pulse generators. Passive procedures require a standardized protocol of the desired activity to ensure repeatability and consistency of the experiment and the results. 3. Transducers: electrodes, sensors. 4. Signal conditioning equipment: amplifiers, filters. 5. Display equipment: 6. Recording, data processing, and transmission equipment: analog instrumentation tape recorders, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), digital tapes, compact disks (CDs), diskettes, computers, telemetry systems. 7. Control devices: power supply stabilizers and isolation equipment, patient intervention systems.  Invasive versus noninvasive procedures: Invasive procedures involve the placement of transducers or other devices inside the body, such as needle electrodes to record MUAPs, or insertion of catheter-tip sensors into the heart via a major artery or vein to record intracardiac signals. Noninvasive procedures are desirable in order to minimize risk to the subject. Recording of the ECG using limb or chest electrodes, the EMG with surface electrodes, or the PCG with microphones or accelerometers placed on the chest are noninvasive procedures.  Active versus passive procedures: 1..Active data acquisition procedures require external stimuli to be applied to the subject, or require the subject to perform a certain activity to stimulate the system of interest in order to elicit the desired response or signal. For example, recording an EMG signal requires contraction of the muscle of interest, such as clenching a fist; recording the VAG signal from the knee requires flexing of the leg over a certain joint angle range; and recording visual ERP signals requires the delivery of flashes of light to the subject. While these stimuli may appear to be innocuous, they do carry risks in certain situations for some subjects: Flexing the knee beyond a certain angle may cause pain for some subjects; and strobe lights may trigger epileptic seizures in some subjects. The investigator should be aware of such risks, 2.. Passive procedures do not require the subject to perform any activity. Recording of the ECG using limb or chest electrodes, the EEG during sleep using scalp-surface electrodes, or the PCG with microphones or accelerometers placed on the chest are passive procedures, but require contact between the subject and the instruments. Note that although the procedure is passive, the system of interest is active under its own natural control in these procedures. Acquiring an image of a subject with reflected natural light (with no flash from the camera) or with the natural infrared (thermal) emission could be categorized as a passive and noncontact procedure.