Patent
Circuit arrangement for digitally processing a given number of channel signals
TLDR
In this article, a recursive digital filter and delay circuits are arranged in cascade there with a discrete Fourier transformer connected to the signal paths, such that the difference between such a phasefrequency characteristic and the phase-frequency characteristic of a reference digital filter has a sawtooth-shaped variation.Abstract:
An arrangement for digitally processing a given number of analog channel signals, more particularly a digital multiplexer and demultiplexer provided with a number of signal paths each comprising a recursive digital filter and delay circuits arranged in cascade therewith, said filter circuits having an amplitude-frequency characteristic of a lowpass filter having a cut-off frequency which is equal to half the bandwidth of a channel signal and a phase-frequency characteristic which is such that the difference between such a phase-frequency characteristic and the phase-frequency characteristic of a reference digital filter has a sawtooth-shaped variation, the slope of the sawtooth being opposite to the slope of the cooperating delay circuit. The arrangement furthermore comprises in cascade a discrete Fourier transformer connected to the signal paths.read more
Citations
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Patent
Digital filter bank
TL;DR: In this article, a digital filter bank for frequency separation of a frequency-multiplexed signal scanned at the detection frequency fA, in which the sums of the products of the detected values of the input signal with the finite pulse reply of the filter bank are subjected to a discrete Fourier transform (DFT) to form L complex output signals.
Patent
Arrangement for processing auxiliary signals in a frequency multiplex transmission system
TL;DR: In this article, a circuit for converting into an FDM format spatially separated signalling signals and pilot signals, comprises a digital filter bank for converting the signals into the FDM formats.
Journal ArticleDOI
Design of a 24-channel transmultiplexer
M. Narasimha,A. Peterson +1 more
TL;DR: The design of a transmultiplexer capable of performing the bilateral conversion between one 1544 kbit/s digital signal and two analog group signals and it is shown that an FIR filter bank required as part of such a trans multiplexer can be realized efficiently by cascading a discrete cosine transform processor and a weighting network.
Patent
Digital filter bank
TL;DR: In this article, the authors proposed a digital filter for modulating and demodulating in frequency division multiplexing systems, where a weighting network weights the transformed samples with predetermined weighting coefficients to form a frequency-division multiplexed signal with proper passband characteristics.
Patent
Digital SSB-FDM communication system derived from a complex band-pass digital filter bank and by a filter breakdown process
TL;DR: In this paper, the phase offsets are provided in the modulator by a post-processor following a conventional DFT processor and in the demodulators by a pre-processor prior to conventional ODFT, which is called an offset discrete Fourier transform (ODFT) processor and supplied with real baseband sample sequences.
References
More filters
Patent
Nonrecursive digital filter apparatus employing delayedadd configuration
TL;DR: In this paper, the delay introduced by each of the delay units of a non-recursive digital filter is selectively altered by employing an alternating series of two-input adders and partial sum delay units to perform the required addition of weight signal samples.
Patent
Universal digital filter for linear discrete systems
Marcian E Hoff,Patrick E Mantey +1 more
TL;DR: In this article, a second-order recursive digital filter is proposed for use as a universal building block in which a first summing means is provided for cyclically computing the function f(n) CX(n)+ 2( Alpha + 2)f(n-1)-f( n-2)+ Beta 1(( Alpha +2)f (n)-1)-F(n)-2)) where X n is a sampled input signal in digital form, f n-1 is the function that delayed one computational cycle by a first unit operator and f n −2 is
Patent
Frequency division multiplex single-sideband modulation system
TL;DR: In this article, a frequency division multiplex single-sideband modulation system using a multiplexed digital filter, the passband of which is sequentially shifted from one multiplex-ed channel to another in synchronization with an input time-division multiplex commutator and a frequency multiplexer modulator.
Patent
Digital transmission system
TL;DR: In this article, the intersymbol interferences at the sampling points spaced by one and two time slots apart from the center sampling point of the single pulse response in the transmission line are detected and used to automatically control the optimum phases of the recovered clock signal and carrier.