2,790 research outputs found
Digital data transition tracking loop improves data reception
Transition tracking loop eliminates drifts, leakages, and instabilities inherent in analog filters. Major components are the phase detector, loop filter, voltage-controlled oscillator and timing logic
Analog filtering in instrumentation using posicast
Analog filters are essential in industrial environments for noise reduction. The filter approximation that presents the best performance in noise reduction is Tchebyshev. This approximation introduces distortions in pulsed signals due to overshoot. The analysis and design of analog filters using a Posicast element are presented. Posicast is a feedforward compensator that reduces overshoot in system response. The authors present a direct method to design analog filters using Posicast, which is based on knowledge of the step response overshoot and system's damped time response period. Simulated results for two filters (Tchebyshev and Bessel) indicates that the new method reduces distortion in pulsed signals, without affecting its performance in frequency
On Out-of-Band Emissions of Quantized Precoding in Massive MU-MIMO-OFDM
We analyze out-of-band (OOB) emissions in the massive multi-user (MU)
multiple-input multiple-output (MIMO) downlink. We focus on systems in which
the base station (BS) is equipped with low-resolution digital-to-analog
converters (DACs) and orthogonal frequency-division multiplexing (OFDM) is used
to communicate to the user equipments (UEs) over frequency-selective channels.
We demonstrate that analog filtering in combination with simple
frequency-domain digital predistortion (DPD) at the BS enables a significant
reduction of OOB emissions, but degrades the
signal-to-interference-noise-and-distortion ratio (SINDR) at the UEs and
increases the peak-to-average power ratio (PAR) at the BS. We use Bussgang's
theorem to characterize the tradeoffs between OOB emissions, SINDR, and PAR,
and to study the impact of analog filters and DPD on the error-rate performance
of the massive MU-MIMO-OFDM downlink. Our results show that by carefully tuning
the parameters of the analog filters, one can achieve a significant reduction
in OOB emissions with only a moderate degradation of error-rate performance and
PAR.Comment: Presented at the 2017 Asilomar Conference on Signals, Systems, and
Computers, 6 page
Optimized Quality Factor of Fractional Order Analog Filters with Band-Pass and Band-Stop Characteristics
Fractional order (FO) filters have been investigated in this paper, with
band-pass (BP) and band-stop (BS) characteristics, which can not be achieved
with conventional integer order filters with orders lesser then two. The
quality factors for symmetric and asymmetric magnitude response have been
optimized using real coded Genetic Algorithm (GA) for a user specified center
frequency. Parametric influence of the FO filters on the magnitude response is
also illustrated with credible numerical simulations.Comment: 6 pages, 13 figures; 2012 Third International Conference on
Computing, Communication and Networking Technologies (ICCCNT'12), July 2012,
Coimbator
Simulation and Realization of Some CMOS-Transconductor Vhf Filters
CMOS circuits for integrated analog filters at very high frequencies have been designed through PSPICE based on the Transconductance-C integrator. They have been implemented on the bread board and many filters i.e. LP, BP, Elliptic LP etc. are simulated and realized
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