EE 5340 Name:___________________

May 7, 1997 Signature^* :___________________

Instructor: C. Davila

1. Design a DDD pacemaker that limits the minimum heart rate to 50 BPM. The maximum allowable PR interval is 400 ms. Draw a block diagram of your design.

(10 pts)

2. During a doppler flowmeter test, the physician mistakingly moves the flowmeter in a direction away from the direction of flow, the geometry is as follows:

calculate the Doppler frequency shift measured by the flowmeter assuming a 2 MHz transmission frequency. Assume that both the transmitter and receiver transducers are moved in the same direction and at the same, constant velocity. (10 pts)

3. Describe how the bandwidth (i.e. f_n) of an extravascular catheter-based blood pressure sensor is affected by the following:

(a) air bubble in catheter saline solution

(b) pinching catheter so that its effective radius decreases

(c) saline solution in catheter is displaced by blood

(10 pts)

4. (a) A Fleisch pneumotachometer has 50 one mm-diammeter capillary tubes in it. Assume that respiratory flow can be modeled as a 1/2 Hz sinusoid, , determine the instantaneous pressure drop across the capillary tubes. (b) Design a linear system that will convert an arbitrary pressure drop signal to a flow signal in a Fleisch pneumotachometer. (Hint: look at material in lecture #1). (10 pts)