摘要:
Verfahren zur Erzeugung eines FDM-Signals hoher Kanalzahl für Übertragungszwecke in Rundfunk- und Fernseh-Verteilsystemen, wobei die mit einer einheitlichen Abtastrate abgetasteten und digitalisierten Kanal-Signale jeweils in interpolierenden digitalen Frequenzumsetzern unter Erhöhung der Abtastrate frequenzumgesetzt und zu dem FDM-Signal zusammengefaßt werden, wobei die frequenzumgesetzten Signale komplexwertige Signale sind, welche mittels eines komplexen Addierers zusammengefaßt und in einer zweiten Stufe mittels Filter mit komplexwertigen Koeffizienten unter weiterer Erhöhung der Abtastrate frequenzumgesetzt und in reelle Signale umgewandelt werden, welche mittels eines reellen Addierers zu dem FDM-Signal zusammengefaßt werden, dadurch gekennzeichnet, daß zur Separierung der einzelnen Kanal- bzw. Kanalbündelsignale aus dem FDM-Signal die zur Aufbereitung desselben angewendeten Verfahrensschritte einer Hermite'schen Transposition unterzogen und angewendet werden. Einsatz in einem Rundfunk- und Fernsehverteilsystem, insbesondere bei Glasfaser, welches eine hohe Kanalzahl und einen lokalen Austausch von Programmen bei hoher Flexibilität und Rekonfigurierbarkeit an beliebigen Stellen mittels aufwandsarmer Einzelkanalbandfilter erlaubt.
摘要:
An FDM-TDM transmultiplexing system for a modulation demodulation device which is applicable to a regenerative repeating system of a satellite or a ground radio communication system is disclosed which uses chirp-z-transform. A chirp filter (102) is implemented with a digital circuit. The circuit scale of the digital chirp filter (102) increases in proportion to a square root of the total number of channels N, enhancing miniaturization of an FDM-TDM transmultiplexer (100A).
摘要:
The invention relates to a bus system for transmitting data between data processing units (20) in a network, by means of a bus (14) that consists of two signal lines. The signals at said bus (14) are analogue signals which lie within a plurality of non-overlapping frequency bands assigned to the individual data processing units (20), and these data processing units (20) use a digital communication protocol to communicate with a signal processor unit (24) that comprises a polyphase filter bank, a D/A converter (26) and a bus-coupling unit (30) being connected downstream of said bank in order to couple the data signal into the bus (14) in a galvanically-isolated manner. The proposed bus system has a simple design with regard to cabling, allows the use of a standard communication protocol such as Ethernet for the data processing units (20), and additionally allows data to be transmitted between all network subscribers simultaneously and without restriction.
摘要:
A system for communicating information between a detection device and a wireless device is provided. The system generally includes a detection device adapted to monitor a condition related to a power system. A radio interface unit is in communication with the detection device via a communication member. A wireless device is further provided which is in radio communication with the radio interface unit such that the detection device communicates information to the wireless device through a radio interface unit. The system's components are further adapted to endure harsh conditions (e.g., prolonged exposure to water).
摘要:
The circuit has an input signal which is filtered with a first filter having a bandwidth greater than a bandwidth of the desired signal. The filtered signal is then sampled to generate discrete time samples, which is then filtered with a discrete time matched filter. The filtered samples are then scaled with a scaling factor and quantized. A quantity related to an amplitude of the quantized samples is measured, and the scaling factor is adjusted in accordance with the measured quantity. The quantized samples can be further processed and provided to a decoder. The desired signal can be a quadrature modulated signal. The adjustment of the scaling factor can be performed by an automatic gain control (AGC) loop that compares the measured signal power of the quantized samples against a predetermined value to generate error values. The AGC loop then filters the error values to generate the scaling factor.
摘要:
A digital receiver (200) and a transmitter (300), wherein the digital receiver includes a plurality of antennas (202) for receiving uplink radio frequency signals; a plurality of analog to digital converters (210) for converting the received radio frequency signals into digital signals; a switched digital down converter (214) for down converting one of the digital signals to a baseband IF signal; and a channel processor (228) for recovering one of a plurality of communication channels contained within the baseband IF signal.