1. A soft decision circuit for determining a most likely data content of a differential phase-shift keying (DPSK) modulated optical signal from three differentially detected intermediate signals that are based on comparisons between pairs of a series of three contiguous data bits of the DPSK modulated optical signal, the soft decision circuit comprising:
a plurality of comparators, each comparator comparing two of the three intermediate signals and generating a digital signal in accordance with the comparison; and
digital logic, the digital logic determining a most likely data content based on the comparator signals, wherein:
G=NORAND(B>\u2212C, A>\u2212B), AND(B>A, B>C),
where A represents a first of the intermediate signals based on a comparison between the first and second of the series of three contiguous data bits, B represents a second of the intermediate signals based on a comparison between the second and third of the series of three contiguous data bits, C represents a third of the intermediate signals based on a comparison between the first and third of the series of three contiguous data bits, and G represents the most likely data content.
2. The soft decision circuit of claim 1, wherein the DPSK signal is a differential binary phase-shift keying (DBPSK) signal.
3. The soft decision circuit of claim 1, wherein the plurality of comparators includes four comparators and the digital logic includes two AND gates coupled to the four comparators and a NOR gate coupled to the two AND gates.
4. A soft detection circuit comprising the soft decision circuit of claim 1.
5. The soft detection circuit of claim 4 comprising:
a three-chip DPSK detection circuit, wherein the three-chip DPSK detection circuit generates the three differentially detected intermediate signals.
6. The soft detection circuit of claim 5, wherein at least one of the three differentially detected intermediate signals is attenuated according to a weighting factor.
7. A soft decision circuit for determining a most likely data content of a differential phase-shift keying (DPSK) modulated optical signal from three differentially detected intermediate signals that are based on comparisons between pairs of a series of three contiguous data bits of the DPSK modulated optical signal, the soft decision circuit comprising:
a plurality of comparators, each comparator comparing two of the three intermediate signals and generating a digital signal in accordance with the comparison; and
digital logic, the digital logic determining a most likely data content based on the comparator signals, wherein the digital logic selects the largest of a plurality of decision variables qij, wherein;
q00=A+B+C,
q01=\u2212A+B\u2212C,
q10=A\u2212B\u2212C,
q11=\u2212A\u2212B+C,
where A represents a first of the intermediate signals based on a comparison between the first and second of the series of three contiguous data bits, B represents a second of the intermediate signals based on a comparison between the second and third of the series of three contiguous data bits, C represents a third of the intermediate signals based on a comparison between the first and third of the series of three contiguous data bits, and qijrepresents the likelihood of a bit sequence ij.
8. The soft decision circuit of claim 7, wherein the DPSK signal is a differential binary phase-shift keying (DBPSK) signal.
9. A soft detection circuit comprising the soft decision circuit of claim 7.
10. The soft detection circuit of claim 9 comprising:
a three-chip DPSK detection circuit, wherein the three-chip DPSK detection circuit generates the three differentially detected intermediate signals.
11. The soft detection circuit of claim 10, wherein at least one of the three differentially detected intermediate signals is attenuated according to a weighting factor.
12. A soft decision circuit for determining a most likely data content of a differential phase-shift keying (DPSK) modulated optical signal from three differentially detected intermediate signals that are based on comparisons between pairs of a series of three contiguous data bits of the DPSK modulated optical signal, the soft decision circuit comprising:
a plurality of comparators, each comparator comparing two of the three intermediate signals and generating a digital signal in accordance with the comparison; and
digital logic, the digital logic determining a most likely data content based on the comparator signals, wherein;
G1=NORAND(A>\u2212B, B>\u2212C), AND(B>A, B>C),
G2=NORAND(A>\u2212B, A>\u2212C), AND(NOT(B>A), A>C),
where A represents a first of the intermediate signals based on a comparison between the first and second of the series of three contiguous data bits, B represents a second of the intermediate signals based on a comparison between the second and third of the series of three contiguous data bits, C represents a third of the intermediate signals based on a comparison between the first and third of the series of three contiguous data bits, G1 represents a first bit of the most likely data content and G2 represents a second bit of the most likely data content.
13. A soft detection circuit comprising the soft decision circuit of claim 12.
14. The soft detection circuit of claim 13 comprising:
a three-chip differential phase-shift-keying (DPSK) detection circuit, wherein the three-chip DPSK detection circuit generates the three differentially detected intermediate signals.
15. The soft detection circuit of claim 14, wherein at least one of the three differentially detected intermediate signals is attenuated according to a weighting factor.
16. The soft decision circuit of claim 12, wherein the DPSK signal is a differential binary phase-shift keying (DBPSK) signal.
17. The soft decision circuit of claim 12, wherein the plurality of comparators includes six comparators and the digital logic includes four AND gates coupled to the six comparators, and two NOR gates coupled to the four AND gates.
18. The soft decision circuit of claim 17, comprising an interleaver coupled to the NOR gates.
19. A soft detection circuit comprising:
a three-chip differential phase-shift keying (DPSK) detection circuit, wherein the three-chip DPSK detection circuit generates a plurality of differentially detected intermediate signals based on comparisons between pairs of a series of three contiguous data bits of a DPSK modulated optical signal and wherein one of the three differentially detected intermediate signals is based on a comparison between the first and third of the series of three contiguous data bits and said one of the three differentially detected intermediate signals is attenuated according to a weighting factor; and
a soft decision circuit for determining a most likely data content of the DPSK modulated optical signal from the plurality of differentially detected intermediate signals, the soft decision circuit including:
a plurality of comparators, each comparator comparing two of the plurality of intermediate signals and generating a digital signal in accordance with the comparison; and
digital logic, the digital logic determining a most likely data content based on the comparator signals.
20. The soft detection circuit of claim 19, wherein the weighting factor is approximately 0.5.
21. The soft detection circuit of claim 19, wherein the DPSK signal is a differential binary phase-shift keying (DBPSK) signal.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A vehicle air suspension system, comprising at least two spring bellows associated with air springs disposed on opposite vehicle sides of an axle of the vehicle, the at least two spring bellows being one of connected to and shut off from a main pressure line via connecting lines having level-regulating valves, the main pressure line being connectable via a main pressure valve alternately to a compressed air source and to a compressed air sink, the connecting lines being connected to one another via a further connecting line having a throttle; and a mechanically activatable shut-off valve coupled to one of the level-regulating valves of the spring bellows such that the mechanically activatable shut-off valve is open when the coupled one of the level-regulating valves is closed and is closed when the coupled one of the level-regulating valves is open.
2. The air suspension system as claimed in claim 1, wherein the further connecting line, the throttle, the mechanically activatable shut-off valve, and the level-regulating valves are disposed in a common valve block.
3. A vehicle air suspension system, comprising at least two spring bellows associated with air springs disposed on opposite vehicle sides of an axle of the vehicle, the at least two spring bellows being one of connected to and shut off from a main pressure line via connecting lines having seat valves, the main pressure line being connectable via a main pressure valve alternately to a compressed air source and to a compressed air sink, the connecting lines being connected to one another via a throttle bore; and a mechanically activatable shut-off valve coupled to one of the seat valves such that the mechanically activatable shut-off valve is open when the coupled one of the seat valves is closed and is closed when the coupled one of the seat valves is open, the mechanically activatable shut-off valve and the seat valves being disposed in a common valve block, wherein the seat valves are arranged in radially adjacent valve bores of a housing of the valve block, the seat valves having valve plates pressed against a valve seats by compression springs via spring disks, wherein the throttle bore connects connecting bores of the seat valves to one another in a connecting cover of the valve block, wherein the mechanically activatable shut-off valve is a further seat valve disposed inside the coupled one of the seat valves, and wherein the mechanically activatable shut-off valve has (i) a valve insert fitted into one of the connecting bores, (ii) a further connecting bore connected via an annular groove to the throttle bore and ending axially in a valve seat, and (iii) a sealing block in contact with one of the spring disks on a side facing away from the valve seat, the sealing block including a sealing element on a side facing towards the valve seat, the sealing block being pressed against the contacted one of the spring disks by a further compression spring.
4. A vehicle air suspension system, comprising at least two spring bellows associated with air springs arranged on opposite vehicle sides of an axle of the vehicle, the at least two spring bellows being one of connected to and shut off from a main pressure line via connecting lines having level-regulating valves, the main pressure line being connectable via a main pressure valve alternately to a compressed air source and to a compressed air sink, the connecting lines being connected to one another via a further connecting line having a throttle; and a mechanically activatable shut-off valve coupled to the main pressure valve such that the shut-off valve is open when the main pressure line is connected to the compressed air source and is closed when the main pressure line is connected to the compressed air sink.
5. The air suspension system as claimed in claim 4, wherein the connecting line, the throttle, the shut-off valve, and the main pressure valve are disposed in a common valve block.