DESIGNING A DIGITAL HIGH-PASS FILTER USING THE CAD ISE DESIGN SUITE

The main features of the "ISE DESIGN SUITE" design environment are considered, using the example of developing a digital high-pass filter using additional software.

Different contra-sound effects between noise and music stimuli seen in N1m and psychophysical responses

Auditory-evoked responses can be affected by the sound presented to the contralateral ear. The different contra-sound effects between noise and music stimuli on N1m responses of auditory-evoked fields and those on psychophysical response were examined in 12 and 15 subjects, respectively. In the magnetoencephalographic study, the stimulus to elicit the N1m response was a tone burst of 500 ms duration at a frequency of 250 Hz, presented at a level of 70 dB, and white noise filtered with high-pass filter at 2000 Hz and music stimuli filtered with high-pass filter at 2000 Hz were used as contralateral noise. The contralateral stimuli (noise or music) were presented in 10 dB steps from 80 dB to 30 dB. Subjects were instructed to focus their attention to the left ear and to press the response button each time they heard burst stimuli presented to the left ear. In the psychophysical study, the effects of contralateral sound presentation on the response time for detection of the probe sound of a 250 Hz tone burst presented at a level of 70 dB were examined for the same contra-noise and contra-music used in the magnetoencephalographic study. The amplitude reduction and latency delay of N1m caused by contra-music stimuli were significantly larger than those by contra-noise stimuli in bilateral hemisphere, even for low level of contra-music near the psychophysical threshold. Moreover, this larger suppressive effect induced by contra-music effects was also observed psychophysically; i.e., the change in response time for detection of the probe sound was significantly longer by adding contralateral music stimuli than by adding contra-noise stimuli. Regarding differences in effect between contra-music and contra-noise, differences in the degree of saliency may be responsible for their different abilities to disturb auditory attention to the probe sound, but further investigation is required to confirm this hypothesis.

Internal gravity wave detection in high-resolution model data

<p>Internal gravity waves (GWs) are ubiquitous in the atmosphere, affecting momentum and energy budgets. However, our understanding of GW effects is still incomplete. As they act on various spatial and temporal scales, global observations of GWs face several difficulties and their parametrizations in climate models employ numerous simplifications and are only poorly constrained. Also, GW analyses in high-resolution datasets contain some uncertainty that we aim to quantify and minimize in our research. We study the uncertainty for a Gaussian high-pass filter method applied on a WRF simulation with horizontal resolution of 3 km covering a domain around the Drake Passage and ranging up to the altitude of 80 km. We show that the momentum flux and drag estimates evaluated by the filtering method are sensitive to the value of a cut-off parameter, especially the horizontal drag components. This motivates us to formulate a new, modified filtering method for GW detection that sets an optimal value of the cut-off parameter at each step based on the spectral information – the method uses a wavelength identified in the horizontal spectrum of kinetic energy. Finally, we note that the type of a response function in the high-pass filter definition also impacts the resulting estimates.</p>

Metode High-Pass Filter Dan Fast Fourier Transform Untuk Perbaikan Citra Telapak Tangan

Telapak tangan sering digunakan sebagai sumber penelitian dibidang sistem biometrik karena mempunyai karakteristik seperti sidik jari. Selain itu, telapak tangan juga mudah didapatkan dan dapat diperoleh dari citra yang memiliki resolusi rendah. Namun, selain itu juga sebuah citra telapak tangan akan dapat mengalami penurunan terhadap kualitasnya. Untuk itu dilakukanlah sebuah tahap yang dikenal dengan perbaikan kualitas citra, dimana bidang ini merupakan tahap awal dari pengolahan citra digital. Dalam penelitian ini penggunaan metode dalam perbaikan citra difokuskan untuk menajamkan citra telapak tangan dengan menggunakan high pass filter dan filter fast fourier transform, dimana sebelumnya citra tersebut telah diolah dengan menggunakan histogram ekualisasi untuk meningkatkan kontras citra telapak tangan. Setelah dilakukan pengujian terhadap 30 sampel citra. Dengan menilai error pada MSE (Mean Square Error) dan PSNR (Peak Signal to Noise Ratio) dari citra hasil rekonstruksi, hasil pengujian menunjukkan bahwa penggunaan high pass filter dengan koefisien=1 menghasilkan citra yang lebih baik dimana nilai rata-rata MSE=7,064544(dB) dan PSNR=40,01314(dB) daripada menggunakan high-pass filter dengan koefisien=0. Sedangkan pada fast fourier transform dengan menggunakan Ideal High-Pass Filter (IHPF) mampu menghasilkan citra rekonstruksi yang lebih baik dengan rerata MSE=9,354056(dB) dan PSNR=38,537046(dB) dari pada menggunakan butterworth high-pass filter (BHPF) dan gaussian high-pass filter (GHPF)

High Pass Filter Application to Reduce Voice Communication Delays on IP Phones

VoIP technology is equipped with several functions, namely, the signalling function, meaning the VoIP is in charge of receiving the network from the caller, after which the conversation delivered. This technology is capable to pass voice traffic in the form of packets over an IP network. Packets of sound undergo a long process or delay to get to the destination it can damage the voice’s quality being heard. It happened because there is continuous delay in the communication between IP phone set on VoIP technology that causes echo in the receiver’s voice. Echo can occur during communication with IP phone set with average delay capacity above 5ms. The delay on the delivery and reception as in the results of communication between telephones can be adjusted for sound frequency of 300 Hz to 1000 Hz as a cut off by adding High Pass Filter (HPF) application. HPF filter application is able to stabilize the amplitude of about -21 dBm from the set of transmission test on the receiver when there is weakening at low frequencies, but when the frequency is raised to 1500-2250 Hz the amplitude strengthens to -12,2 dBm or increases the value of about 8.8 dB. Meanwhile, for the lower frequency such as 300 – 950 Hz, the filter would not pass it since the frequency is designed to be cut-off at 1000 Hz. The value of delay is narrower to 0.08ms by HPF application at the frequency of sound upper limit received by any 1000-3400 Hz telephone set. Keywords: VoIP technology, echo cancelling, HPF filter, delay, voice quality

The Role of 2D Fast Fourier Transform and High Pass Filter in Regional and Residual Anomaly Separation in Gravity

Regional and residual Separation anomaly is one thing that must do in gravity processing data. It is important before calculating the depth of anomaly by power spectrum. There are several ways to do this, one of them is using 2D Fast Fourier Transform (FFT). 2D FFT will calculate the two-dimensional power of the gravity map (Bouger anomaly) to change the spatial domain into the wavenumber domain. 2D FFT result has no unit because it works in the wavenumber domain. Power spectrum do in wavenumber domain map. Besides that, to make the wavenumber map in the frequency domain, it should be convolved with some filter (high–pass filter) and then inverse to separate the regional and the residual map. The design of the filter matrix depends on the number of the data and the location of anomalies will be enhanced. It will influence the separation result. The best result gets from the trial and error process. 2D FFT is act like Upward Continuation or Polynomial Fitting in the gravity method with the simple process. In this paper, the process fully done in Python. Python is an effective and simple language programming because it has many modules to support the processing and covering the big data. It also gives the flexibility to the researcher to determine the specific location that will be enhanced

Neurotransmitter regulation rather than cell-intrinsic properties shape the high-pass filtering properties of olfactory bulb glomeruli

GABAergic periglomerular (PG) cells in the olfactory bulb are proposed to mediate an intraglomerular “high-pass” filter through inhibition targeted onto a glomerulus. With this mechanism, weak stimuli (e.g., an odor with a low affinity for an odorant receptor) mainly produce PG cell-driven inhibition but strong stimuli generate enough excitation to overcome inhibition. PG cells may be particularly susceptible to being activated by weak stimuli due to their intrinsically small size and high input resistance. Here, we used dual-cell patch-clamp recordings and imaging methods in bulb slices obtained from wild-type and transgenic rats with labeled GABAergic cells to test a number of predictions of the high-pass filtering model. We first directly compared the responsiveness of PG cells with that of external tufted cells (eTCs), which are a class of excitatory interneurons that reside in a parallel but opposing position in the glomerular circuitry. PG cells were in fact found to be no more responsive than eTCs at low levels of sensory neuron activity. While PG cells required smaller currents to be excited, this advantage was offset by the fact that a given level of sensory neuron activity produced much smaller synaptic currents. We did however identify other factors that shaped the excitation/inhibition balance in a manner that would support a high-pass filter, including glial glutamate transporters and presynaptic metabotropic glutamate receptors. We conclude that a single glomerulus may act as a high-pass filter to enhance the contrast between different olfactory stimuli through mechanisms that are largely independent cell intrinsic properties.Key Points SummaryGABAergic periglomerular (PG) cells in the olfactory bulb are proposed to mediate a “high-pass” filter at a single glomerulus that selectively blocks weak stimulus signals. Their efficacy may reflect their intrinsically small size and high input resistance, which allows them to be easily excited.We found that PG cells were in fact no more likely to be activated by weak stimuli than excitatory neurons. PG cells spiked more readily in response to a fixed current input, but this advantage for excitability was offset by small synaptic currents.Glomeruli nevertheless display an excitation/inhibition balance that can support a high pass filter, becoming much more favorable with increasing stimulus strength. Factors shaping the filter include glial glutamate transporters and presynaptic metabotropic glutamate receptors.We conclude that a single glomerulus may act as a high-pass filter to enhance stimulus contrast through mechanisms that are largely independent of cell-intrinsic properties.