Bus system using plurality of non-overlapping frequency bands for communication
View Patent ↗The invention relates to a bus system for transmitting data between data processing units in a network, by means of a bus that consists of two signal lines. The signals at said bus are analog signals which lie within a plurality of non-overlapping frequency bands assigned to the individual data processing units, and these data processing units use a digital communication protocol to communicate with a signal processor unit that comprises a polyphase filter bank, a D/A Converter and a bus-coupling unit being connected downstream of said bank in order to couple the data signal into the bus 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, and additionally allows data to be transmitted between all network subscribers simultaneously and without restriction.
1. A bus system associated with a network partitioned into multiple virtual connections, the bus system comprising:
a bus having two signal lines with analog signals applied on the bus within non-overlapping frequency bands;
a plurality of data processing units, each of the data processing units assigned with a distinct non-overlapping mid-frequency band, the bus connecting the data processing units to the network using direct point-to-point or point-to-multipoint virtual connections based at least on one distinct non-overlapping mid-frequency band; and
a modem unit coupling each data processing unit with the bus using the two signal lines of the bus, the modem unit comprising:
an interface unit connectable with each data processing unit to communicate using the direct point-to-point or point-to-multipoint virtual connections with each data processing unit using a digital communication protocol;
a modulation unit that converts flow of data into a signal that is transferable using the non-overlapping frequency bands;
a filter bank synthesis unit comprising a polyphase filter bank that converts the data of the interface unit on the distinct mid-frequency band assigned to the data processing unit and suppresses interferences between adjacent non-overlapping frequency bands;
a D/A converter that converts the signal of the filter bank synthesis unit into an analog signal;
a bus-coupling unit configured to inductively or capacitively couple the analog signal of the D/A converter that is transmitted onto the bus in a galvanically isolated manner, and to inductively or capacitively decouple one or more analog signals received from the bus in a galvanically isolated manner;
an A/D converter that digitizes the analog signals received from the bus-coupling unit;
a filter bank analysis unit comprising a polyphase filter bank that partitions the digitized signals into the distinct non-overlapping frequency bands, and feeds data to the interface unit based on its assigned non-overlapping frequency band; and
a demodulation unit that demodulates the data of the filter bank analysis unit, and feeds user data to the interface unit, wherein the bus system transmits data using the direct point-to-point or point-to-multipoint virtual connections while minimizing interference between the multiple virtual connections, wherein only every second frequency band of the non-overlapping frequency bands is utilized exclusively.
2. The bus system according to claim 1 , wherein 2 n (n=1 to 6) frequency bands are provided.
3. The bus system according to claim 1 , wherein a first analog low-pass filter is arranged between the D/A converter and the bus-coupling unit.
4. The bus system according to claim 1 , wherein a second analog low-pass filter is arranged between the A/D converter and the bus-coupling unit.
5. The bus system according to claim 1 , wherein on a transmission side of the bus-coupling unit, a driver unit is arranged upstream.
6. The bus system according to claim 1 , wherein data encoding in the modulation unit is performed using quadrature amplitude modulation.
7. The bus system according to claim 1 , wherein the digital communication protocol is IEEE 802.3 (Ethernet), ARINC-429, MIL-STD-1553 or CAN.
8. The bus system according to claim 1 , wherein 8 frequency bands with mid-frequencies of n*0.625 MHz (n=1 . . . 7) are provided.
9. An aircraft comprising a bus system associated with a network partitioned into multiple virtual connections, the bus system comprising:
a bus having two signal lines with analog signals applied on the bus within non-overlapping frequency bands;
a plurality of data processing units, each of the data processing units assigned with a distinct non-overlapping mid-frequency band, the bus connecting the data processing units to the network using direct point-to-point or point-to-multipoint virtual connections based at least on one distinct non-overlapping mid-frequency band; and
a modem unit coupling each data processing unit with the bus using the two signal lines of the bus, the modem unit comprising:
an interface unit connectable with each data processing unit to communicate using the direct point-to-point or point-to-multipoint virtual connections with each data processing unit using a digital communication protocol;
a modulation unit that converts flow of data into a signal that is transferable using the non-overlapping frequency bands;
a filter bank synthesis unit comprising a polyphase filter bank that converts the data of the interface unit on the distinct mid-frequency band assigned to the data processing unit and suppresses interferences between adjacent non-overlapping frequency bands;
a D/A converter that converts the signal of the filter bank synthesis unit into an analog signal;
a bus-coupling unit configured to inductively or capacitively couple the analog signal of the D/A converter that is transmitted onto the bus in a galvanically isolated manner, and to inductively or capacitively decouple one or more analog signals received from the bus in a galvanically isolated manner;
an A/D converter that digitizes the analog signals from the bus-coupling unit;
a filter bank analysis unit comprising a polyphase filter bank that partitions the digitized signals into the distinct non-overlapping frequency bands, and feeds data to the interface unit based on its assigned non-overlapping frequency band; and
a demodulation unit that demodulates the data of the filter bank analysis unit, and feeds user data to the interface unit, wherein the bus system transmits data using the direct point-to-point or point-to-multipoint virtual connections while minimizing interference between the multiple virtual connections, wherein only every second frequency band of the non-overlapping frequency bands is utilized exclusively.
10. The aircraft according to claim 9 , wherein 2 n (n=1 to 6) frequency bands are provided.
11. The aircraft according to claim 9 , wherein a first analog low-pass filter is arranged between the D/A converter and the bus-coupling unit.
12. The aircraft according to claim 9 , wherein a second analog low-pass filter is arranged between the A/D converter and the bus-coupling unit.
13. The aircraft according to claim 9 , wherein on a transmission side of the bus-coupling unit, a driver unit is arranged upstream.
14. The aircraft according to claim 9 , wherein data encoding in the narrowband modulation unit is performed using quadrature amplitude modulation.
15. The aircraft according to claim 9 , wherein the digital communication protocol is IEEE 802.3 (Ethernet), ARINC-429, MIL-STD-1553 or CAN.
16. The aircraft according to claim 9 , wherein 8 frequency bands with mid-frequencies of n*0.625 MHz (n=1.7) are provided.