Bessel filter

About: Bessel filter is a research topic. Over the lifetime, 656 publications have been published within this topic receiving 16808 citations.

A direct detection method for DPSK/DQPSK signals

Abstract: In this letter, a kind of receiver based on optical Bessel filter for DPSK/DQPSK signals direct detection is discussed By using this receiver, good spectrums and back-to-back eye-diagrams for CSRZ-DPSK and CSRZ-DQPSK can be achieved respectively in simulation Compared the traditional balanced receiver, it is simple, effective, and low costive for DPSK/DQPSK signals detection

Note on the Computation of the Bessel Function _

Abstract: This procedure, however, affords another example in which great accuracy is needed to start with (as has been pointed out in case of /„(s) by Cosens [MTAC p. 99]), since more and more accuracy is lost at each step. The value of i\"9o(60) = 0.0725775• • would, if computed this way, require about 40 decimal places in /o(60) and 7i(60), and 89 applications of (3). Nicholson3 has given a formula for In(x) purporting to be \"suitable for rapid tabulation,\" when either n or x is large. The formula is not given explicitly (except its first term) but in terms of an infinite differential operator with undetermined coefficients operating on a cumbersome function of n and x. The following formula, which I have not found in the literature, is quite effective in case n is large and x has any real value.

Solvable Chaos as a Tool for Evaluating Wideband Delay Cells in Matched Filters

Abstract: We show the development of a wideband delay guided by the closed-form, analytic solution of a solvable chaotic oscillator. This delay serves as a crucial component in the design of a matched filter receiver that optimally detects chaotic waveforms in the presence of noise. Unlike most chaotic systems, a special class of solvable chaos permits a closed-form analytic expression that may be used to guide designs. Specifically, we employ a cascade of 7th-order Bessel filter cells to accommodate various bandwidths associated with these oscillators. These bandwidth increments are guided by a closed form expression of the chaotic signals' spectral content. The resulting delay has wideband frequency characteristics while keeping group delay maximally flat within the operating band. Next, we analyze our results through time series comparison of the delayed signals with corresponding, analytically reconstructed chaotic waveforms. Finally, we summarize the trade-off space for these delay designs informed by analytic solution. Our results show that these finite bandwidth delay designs impose a 13% deviation from analytic time series expectations when 4 spectral lobes are considered and 17 % deviation for 3 spectral lobes.

A CONTINUOUS-TIME FILTER AND EQUALIZER COMPRISING A PARASITIC-INSENSITIVE BiCMOS ACTIVE INTEGRATOR

Abstract: A fast parasitic-insensitive continuous-time filter and equalizer integrated circuit that uses an active integrator is described. Circuit techniques for excess-phase cancellation, and for setting the corner-frequency of the filter and equalizer are also described. These techniques result in a filter and equalizer chip with performance independent of process, supply, and temperature without employing phase-lock loops. This 20MHz 6th order Bessel filter and 2nd order equalizer operate from 5V, and generate only .24 % (-52dB) of total harmonic distortion when processing 2Vp-p differential output signals. The device is optimized to limit high-frequency noise and to amplitude equalize the data pulses in hard disk read-channel systems. The device supports data rates of up to 36Mbps, and is built in a 1.5ν/4GHz BiCMOS technology.

Closed-form representations of the laplace transforms of bessel funtions

Abstract: Closed-form expressions of the Laplace transforms of ordinary Bessel functions , of an evev order can be found in standard compilations for the cases n=0 and b=0 only. Investigations of the Sommerfeld description of inhomogeneous spherical waves led to two such forms, one in terms of modified spherical Bessel functions, and another one involving incomplete gamma funtions.