Ant Nachrichtentechnik Gmbh

Licentia Patent-verwaltungs Gmbh

Robert Boschgmbh

Rheinmetall Gmbh

Aeg-telefunken Ag Licentia Patent-verwaltungs-gmbh

Heinz Gockler

Hagen Hofmeister

Karlheinz Grotz

Heinrich Schenk

Erich Auer

Jurgen Wermuth

Helmut Scheuermann

Hans-Peter Petry

Georg Sussmeier

Harald Ansorge

Reinhard Till

Aerial for a central station of a point-to-multi-point radio link system

A distribution system, useful with radio and television distribution, for distributing a signal having a plurality of channels includes a central station. The central station produces a first frequency division multiplexed signal in which signals from a plurality of channels or channel groups are frequency-converted and combined, and introduces the first frequency division multiplexed signal into transmission media of the distribution system. The first frequency division multiplexed signal may include occupied channels, freely selectable occupied channels, and free channels. A plurality of further stations receive the first frequency division multiplexed signal from the central station and process it with signals of a plurality of further channels to produce a second frequency division multiplexed signal. The signals of the plurality of further channels may be put in free channels, or used to replace signals in freely selectable occupied channels of the first frequency division multiplexed signal. A plurality of user devices receive the second frequency division multiplexed signal from at least one of the plurality of further stations, and split it into individual channel or channel group signals for user access.

Radio and television distribution system

A drop-and-add multiplexer for receiving an incoming FDM signal with a plurality of channels, for receiving signals of additional channels, and for outputting an outgoing FDM signal. The multiplexer includes at least one single channel filter for receiving an incoming FDM signal, filtering the incoming FDM signal by blocking a selected channel frequency, and outputting a filtered FDM signal. At least one interpolating digital frequency converter receives another channel signal which is not in the incoming FDM signal, converts the other channel signal into a channel frequency which has been blocked by the at least one single channel filter or was an empty channel frequency in the incoming FDM signal, and outputs a converted other channel signal. At least one digital frequency converter is provided and includes a cascade connection of a decimating digital frequency converter and an interpolating digital frequency converter, for receiving the incoming FDM signal, frequency-converting a selected channel from an input frequency to a different outgoing frequency, and outputting a frequency-converted channel signal. An adder adds the converted other channel signal output by the interpolating digital frequency converter, the filtered FDM signal output by the single channel filter, and the frequency-converted channel signal output by the digital frequency converter, and outputs an outgoing FDM signal.

Drop-and-add multiplexer for converting and processing a frequency

Device for determining the amplitude of the spectral lines in the output

A method and circuit arrangement for determining angular velocities by means of an optical fiber ring interferometer includes, in addition to, a phase modulator for modulating light waves passing through an optical fiber ring of the interferometer at a phase modulation frequency f, and a device for combining light waves leaving the optical fiber ring to produce an output signal, a unit for generating a sampling frequency f.sub.A according to the following equations: ##EQU1## wherein the factors m and l are integers and f.sub..DELTA. is a whole number component i.e., subharmonic, of the phase modulation frequency. The output signal of the interferometer is sampled at the frequency f.sub.A during conversion via an analog/digital converter into a digital signal. The digitilized signal is evaluated to determine the angular velocity.

Improved method and arrangement for processing output signals of a fiber

Non-recursive half-band filter

A method and circuit arrangement for determining angular velocities with the aid of an optical fiber ring interferometer includes filter circuitry for selecting the amplitudes of four adjacent spectral lines of resultant interfering light waves exiting from the interferometer, a first adder for adding amplitudes of spectral lines at the lowest and second highest frequency, a second adder for adding spectral line amplitudes at the second lowest and the highest frequency, a divider for forming a quotient by dividing a first product of the first adder's sum and the amplitude at the second highest frequency by a second product of the second adder's sum and the second lowest frequency amplitude if the second lowest frequency is an even numbered harmonic of the modulation frequency, and by dividing the second product by the first product if the second lowest frequency is an odd numbered haromonic of the modulation frequency; a first circuit device for weighting the quotient with a ratio of the ordinal of the harmonic which coincides with the second highest spectral line frequency to the harmonic which coincides with the second lowest spectral line frequency if the second lowest spectral line frequency is an even numbered harmonic of the modulation frequency, and with an inverse of the factor if the second lowest spectral line frequency is an odd numbered harmonic of the modulation frequency; and a second circuit device for using the arc tangent function on the square root of the weighted quotient to determine the Sagnac phase.

Method and arangement for determining angular velocities

Non-recursive half-band filter with complex valued coefficients for

A nonrecursive half-band filter which permits the conversion of a complex-value input signal into a complex-value output signal. The pulse response of the filter is modulated onto a complex carrier at a frequency of 1/4 or 3/4 of the sampling rate, the zero phase of this frequency is a whole multiple of .pi./2, and the sampling rate is halved. Another embodiment of the filter also permits the conversion of a complex-value input signal into a complex-value output signal. In the second embodiment the pulse response is modulated onto a complex carrier of a frequency of one-half the input sampling rate, the zero phase of this frequency is a whole number multiple of .pi./2, and the sampling rate is doubled.

Nonrecursive half-band filter

Method and apparatus for processing compressed, stored analog signals, such as audio signals, from a storage medium, including first converting the signals to digital signals and thereafter expanding the signals. To realize a large volume range in the conversion of compressed recorded signals to expand digital signals, the compressed analog signals picked up from a storage medium are initially analog/digital converted and only then digitally expanded.

Method and apparatus for digitally processing stored compressed analog

The invention relates to a digital filter tree composed of a plurality of digital filter banks arranged in a tree structure one behind the other to branch out in stages with a separation into L.sub..nu. individual signals taking place in each stage and the sampling rate being reduced each time by the factor M.sub..nu. where .nu.=1,2, . . . identifies the .nu.th stage. The filter tree employs a prototype filter with half-band functions for channel center frequencies f.sub.l =l.multidot.B+B/2, with a real frequency multiplex input signal being separated into L.sub..nu. complex channel signals for further processing by means of a discrete Fourier transformation. For all stages M.sub..nu. =2 and L.sub..nu. =4 are fixed, with only two signals of the L.sub..nu. =4 being utilized. The arrangement permits adaptation of a hierarchical multi-stage method also to numbers of channels which are not equal to a power of two without changing the input sampling frequency and without the causing channels, whose number is fixed by the difference from the next higher power of two, to idle.

Digital filter tree

A method and apparatus for the transmission of time discrete signals between source and sink systems wherein a first signal x(n) is generated by the source system at a first sampling rate f.sub.i and a second time discrete signal y(m) is generated by a sink system at a second sampling rate f.sub.0. The method is carried out by cyclically distributing the first time discrete signal to each of L filter groups at the first sampling rate f.sub.i. Each of the L filter groups comprises M filter elements which have their inputs connected to a common terminal and have the transfer function H.sub.l,m (z.sup.LM, where L and M are integers, l is an integer 0, 1 . . . L-1 corresponding to the filter group in which the filter element is located and m is an integer 0, 1 . . . M-1 corresponding to the location of the filter element in its associated filter group. The first time discrete signal is filtered in each of the filter elements at a processing rate f.sub.i /L and the filtered signals stored in the filter elements. Thereafter, the stored outputs of the M filter elements in each of the L filter groups are cyclically sampled at the second sampling rate f.sub.0 and coupled to corresponding inputs of a summing element which generates a signal f.sub.0 at its output equal to M/L f.sub.i.

Method and apparatus for the transmission of time discrete signals

A system for the digital conversion of a time division multiplex signal into a frequency division multiplex signal wherein the signals of the individual time multiplex channels are filtered by means of bandpass filters, their sampling rates are increased by the factor N to fA and the output signals of these bandpass filters are combined, by means of a summing member, into the frequency multiplex signal, and/or a system for the digital conversion of a frequency multiplex signal into a time division multiplex signal, wherein the digitalized frequency multiplex signal is divided by means of respective bandpass filters into the signals of the individual frequency multiplex channels and their sampling rate fA is reduced by the factor N. The individual bandpass filters (BP) are designed as recursive filters having the transfer function

Digital transmultiplexer

In a receiver for synchronously demodulating real bandpass signals and including circuit elements connected for removing noise, equalizing the signals, converting the resulting signals to analytical signals, shifting the signals in phase, sampling the signals at the signal element timing rhythm, and interrogating the sampled signals, there is provided a single pair of filters serving to perform both the equalizing and converting functions.

Receiver for effecting synchronous demodulation

A method for digitally regulating the residual carrier phase error in receivers of digital data transmission systems. A comparator compares the sampled data signal or value of the carrier demodulated input signal to the receiver with the estimated value for each associated sampling time or moment as provided by a decider, to determine the deviation dk which is a measure for the phase difference between the sampled value and the associated estimated value. This deviation dk is filtered in a digital loop filter, including a proportional branch and an integration branch, and a regulating value for the demodulated input signal is obtained from a subsequently connected accumulator. A non-linear limitation on the deviation dk is included in the integration branch of the digital loop filter.

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Backnang, Germany

Heinz Gockler