Abstract
The nucleus laminaris of the barn owl auditory system is quite impressive, since its underlying time estimation is much better than the processing speed of the involved neurons. Since precise localization is also very important in many technical applications, this paper explores to what extent the main principles of the nucleus laminaris can be implemented in digital hardware. The first prototypical implementation yields a time resolution of about 20 ps, even though the chosen standard, low-cost device is clocked at only 85 MHz, which leads to an internal duty cycle of approximately 12 ns. In addition, this paper also explores the utility of an advanced sampling scheme, known as unfolding-in-time. It turns out that with this sampling method, the prototype can easily process input signals of up to 300 MHz, which is almost four times higher than the sampling rate.
Highlights
The barn owl auditory system constitutes an impressive localization system (Kempter et al, 1996)
The axonal delay lines change the mutual timing between the two signals that are originating at the two ears; the timing between the two signals is unique at every coincidence detector
As has already been seen in the barn owl auditory system, XORCA employs a large number of coincidence detectors, which are all connected to two reciprocal “delay” wires w1 and w2 on which the two signals r1(t ) and r2(t ) travel with approximately two third of the speed of light cw ≈ 2/3c
Summary
The barn owl auditory system constitutes an impressive localization system (Kempter et al, 1996). A further challenge is induced, if electromagnetic signals are to be used, which is often the case; because electromagnetic signals travel with the speed of light c = 3 × 108 m/s, a resolution of 1 cm corresponds to approximately 30 ps, which cannot be achieved with currently available low-cost digital systems Because of these requirements, this paper investigates to which extent the main principles of the nucleus laminaris can be realized in digital hardware. Depending on the location of the sound source, all the neurons exhibit different activities This scheme allows for signal frequencies way above the sampling rate; the first prototype processes up to 300 MHz as is shown, even though the sampling rate is still at 85 MHz. Section VII concludes this paper with a brief discussion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
