Paradoxical reference frequency shifts during paired flights in Japanese horseshoe bats evaluated with a Telemike.

2010 ◽  
Vol 127 (3) ◽  
pp. 1971-1971
Author(s):  
Yuto Furusawa ◽  
Shizuko Hiryu ◽  
Hiroshi Riquimaroux
Keyword(s):  
Reference Frequency ◽  
Frequency Shifts ◽  
Horseshoe Bats

scholarly journals Auditory-Feedback Control of Temporal Call Patterns in Echolocating Horseshoe Bats

2005 ◽  
Vol 93 (3) ◽  
pp. 1295-1303 ◽  
Author(s):  
Michael Smotherman ◽  
Walter Metzner
Keyword(s):  
Auditory Feedback ◽  
Dependent Manner ◽  
Constant Frequency ◽  
Frequency Shifts ◽  
Call Duration ◽  
Calling Patterns ◽  
Neural Feedback ◽  
Auditory Feedback Control ◽  
Horseshoe Bats ◽  
Echo Delay

During flight, auditory feedback causes horseshoe bats to adjust the duration and repetition rate of their vocalizations in a context-dependent manner. As these bats approach a target, they make finely graded adjustments in call duration and interpulse interval (IPI), but their echolocation behavior is also characterized by abrupt transitions in overall temporal calling patterns. We investigated the relative contributions of two prominent acoustic cues, echo frequency and delay, toward the control of both graded and transitional changes in call duration and IPI. Echoes returning at frequencies above the emitted call frequency caused bats to switch from long single calls to pairs of short calls (doublets). Alternatively, increasing echo delay caused progressive increases in IPI but caused no accompanying changes in call duration. When frequency shifts were combined with changing echo delays, echo delay altered the IPIs occurring between doublets but not the IPI within a doublet. When the echo mimic was replaced by presentation of either an artificial constant-frequency (CF) stimulus or a frequency-modulated (FM) stimulus, each designed to mimic major components of the echo acoustic structure, we found that CF stimuli could trigger the switch to doublets, but changing CF delay had no influence on IPI, whereas the timing of an FM-sweep presentation had a strong effect on IPI. Because CF and FM sounds are known to be processed separately in the bat auditory system, the results indicate that at least two distinct neural feedback pathways may be used to control the temporal patterns of vocalization in echolocating horseshoe bats.

Experimental Research on the Acceleration Sensitivity of Quartz Crystal Oscillators

2012 ◽  
Vol 241-244 ◽  
pp. 869-875
Author(s):  
Long Zhe Ji ◽  
Qing Xiao Shan ◽  
Jun Yang ◽  
Ming Lin
Keyword(s):  
Quartz Crystal ◽  
Measuring Method ◽  
Reference Frequency ◽  
Frequency Shifts ◽  
Experiment System ◽  
Vibrating Platform ◽  
Vibration Experiment ◽  
Crystal Oscillators ◽  
The Relationship ◽  
Sensitivity Vector

Quartz crystal oscillators are often used as the reference frequency sources, but they are very sensitive to accelerations. This paper discussed how accelerations affect oscillators’ frequency stability. The frequency shifts caused by gravity was shown through 2g-tipover experiment. Then a vibration experiment system was built up, which consist of the vibrating platform, the controlling part, the measuring part and the oscillator. We studied the relationship between accelerations and oscillator’s frequency shifts by imposing sinusoidal and random vibrations onto the oscillator and observing the phase noise degradation via signal source analyzer. The paper also brought up the measuring method of the acceleration sensitivity vector.

Effects of Echo Intensity on Doppler-Shift Compensation Behavior in Horseshoe Bats

2003 ◽  
Vol 89 (2) ◽  
pp. 814-821 ◽  
Author(s):  
Michael Smotherman ◽  
Walter Metzner
Keyword(s):  
Doppler Shift ◽  
Reference Frequency ◽  
Frequency Compensation ◽  
Echo Intensity ◽  
Experimental Conditions ◽  
Emission Frequency ◽  
Delay Duration ◽  
Compensation Behavior ◽  
Systematic Shift ◽  
Horseshoe Bats

Echolocating horseshoe bats respond to flight-speed induced shifts in echo frequency by adjusting the frequency of subsequent calls. Under natural conditions, Doppler effects may force the frequency of a returning echo several kilohertz above the original emission frequency. By lowering subsequent call frequencies, the bat can return echo frequencies to within a narrow spectral bandwidth to which its highly specialized auditory system is most sensitive. While Doppler-shift compensation (DSC) behavior specifically refers to frequency compensation, other parameters of the returning echo, such as delay, duration, and interaural time and intensity differences have been shown to influence DSC performance. Understanding the nature of these influences has already led to a better appreciation of the neurophysiology of DSC. Here we provide a quantitative analysis of the effects of a prominent feature of the returning echo, its intensity, on DSC performance in horseshoe bats. Although DSC performance generally tolerates echo attenuation up to approximately 40 dB relative to the outgoing emission intensity, a systematic decline in DSC performance can be observed over this range. Generally, the effects of echo attenuation are characterized by a reduction in 1) the overall amount of compensation relative to the size of the shift in echo frequency and 2) the rate at which the bat responds to perceived echo shifts. These effects appear to be the consequence of a systematic shift in the range of echo frequencies capable of inducing DSC behavior. In particular, the reference frequency (the minimum shift in echo frequency that will elicit DSC behavior) appears to be highly sensitive to echo intensity. Every 10-dB reduction in echo intensity shifts the reference upward nearly 250 Hz. Our results indicate that, even at the highest intensity levels, relatively minor changes in echo intensity critically influence frequency compensation during normal DSC. We conclude with a discussion of how these results might impact echolocation behavior of horseshoe bats under natural and experimental conditions.

The Behaviour and Vocalisations of Captive Geoffroy's Horseshoe Bats, Rhinolophus clivosus (Chiroptera: Rhinolophidae)

2019 ◽  
Vol 20 (2) ◽  
pp. 439
Author(s):  
Hana Petersen ◽  
Nikita Finger ◽  
Anna Bastian ◽  
David Jacobs
Keyword(s):  
Horseshoe Bats

scholarly journals Patch antenna sensor for wireless ice and frost detection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryan Kozak ◽  
Kasra Khorsand ◽  
Telnaz Zarifi ◽  
Kevin Golovin ◽  
Mohammad H. Zarifi
Keyword(s):  
Resonant Frequency ◽  
Patch Antenna ◽  
Wide Band ◽  
Power Lines ◽  
Ice Thickness ◽  
Ice Accretion ◽  
Robust Method ◽  
Frequency Shifts ◽  
Resonant Amplitude ◽  
Recorded Data

AbstractA patch antenna sensor with T-shaped slots operating at 2.378 GHz was developed and investigated for wireless ice and frost detection applications. Detection was performed by monitoring the resonant amplitude and resonant frequency of the transmission coefficient between the antenna sensor and a wide band receiver. This sensor was capable of distinguishing between frost, ice, and water with total shifts in resonant frequency of 32 MHz and 36 MHz in the presence of frost and ice, respectively, when compared to the bare sensor. Additionally, the antenna was sensitive to both ice thickness and the surface area covered in ice displaying resonant frequency shifts of 2 MHz and 8 MHz respectively between 80 and 160 μL of ice. By fitting an exponential function to the recorded data, the freezing rate was also extracted. The analysis within this work distinguishes the antenna sensor as a highly accurate and robust method for wireless ice accretion detection and monitoring. This technology has applications in a variety of industries including the energy sector for detection of ice on wind turbines and power lines.

scholarly journals A Novel Fast-Locking ADPLL Based on Bisection Method

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1382
Author(s):  
Xiaoying Deng ◽  
Huazhang Li ◽  
Mingcheng Zhu
Keyword(s):  
High Performance ◽  
Tuning Range ◽  
Frequency Control ◽  
Control Word ◽  
Cmos Process ◽  
Bisection Method ◽  
Reference Frequency ◽  
Wide Tuning Range ◽  
Cascade Structure ◽  
And Control

Based on the idea of bisection method, a new structure of All-Digital Phased-Locked Loop (ADPLL) with fast-locking is proposed. The structure and locking method are different from the traditional ADPLLs. The Control Circuit consists of frequency compare module, mode-adjust module and control module, which is responsible for adjusting the frequency control word of digital-controlled-oscillator (DCO) by Bisection method according to the result of the frequency compare between reference clock and restructure clock. With a high frequency cascade structure, the DCO achieves wide tuning range and high resolution. The proposed ADPLL was designed in SMIC 180 nm CMOS process. The measured results show a lock range of 640-to-1920 MHz with a 40 MHz reference frequency. The ADPLL core occupies 0.04 mm2, and the power consumption is 29.48 mW, with a 1.8 V supply. The longest locking time is 23 reference cycles, 575 ns, at 1.92 GHz. When the ADPLL operates at 1.28 GHz–1.6 GHz, the locking time is the shortest, only 9 reference cycles, 225 ns. Compared with the recent high-performance ADPLLs, our design shows advantages of small area, short locking time, and wide tuning range.

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