All-pass network for data transmission over a CATV system
First Claim
1. A method for configuring a path of a cable TV system, wherein the path includes from one to a plurality of amplifiers for amplifying signals transmitted along the path to a receiver, the amplifier(s) having diplex filter network(s) for separating forward and return signals, the method comprising the steps of:
- determining a collective delay versus frequency characteristic of the path within the predetermined frequency band caused by the amplifier(s) with diplex filter network(s); and
providing from one to a plurality of all-pass delay equalizers in the path, wherein a collective delay versus frequency characteristic of the all-pass delay equalizer(s) within a predetermined frequency band is substantially a mirror image of that caused by the amplifier(s) with diplex filter network(s), such that all frequencies within the predetermined frequency band are delayed by substantially the same amount and hence all frequency components of a signal occupying the predetermined frequency band arrive at the receiver in the path at substantially the same time.
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Accused Products
Abstract
A cable system, and a method for configuring a path of a cable system, wherein the group delay caused by one or more amplifiers having diplex filter networks is substantially equalized over all frequencies within a predetermined band by the use of one or more all-pass delay equalizers. A method of configuring a path includes steps of determining a delay versus frequency characteristic of the path within the predetermined frequency band, and providing from one to a plurality of all-pass delay equalizers in the path, wherein a collective delay versus frequency characteristic of the all-pass delay equalizer(s) within a predetermined frequency band is a mirror image of that caused by the amplifier(s), such that all frequencies within the predetermined frequency band are delayed by substantially the same amount and hence all frequency components of a signal arrive at a receiver at substantially the same time.
17 Citations
16 Claims
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1. A method for configuring a path of a cable TV system, wherein the path includes from one to a plurality of amplifiers for amplifying signals transmitted along the path to a receiver, the amplifier(s) having diplex filter network(s) for separating forward and return signals, the method comprising the steps of:
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determining a collective delay versus frequency characteristic of the path within the predetermined frequency band caused by the amplifier(s) with diplex filter network(s); and
providing from one to a plurality of all-pass delay equalizers in the path, wherein a collective delay versus frequency characteristic of the all-pass delay equalizer(s) within a predetermined frequency band is substantially a mirror image of that caused by the amplifier(s) with diplex filter network(s), such that all frequencies within the predetermined frequency band are delayed by substantially the same amount and hence all frequency components of a signal occupying the predetermined frequency band arrive at the receiver in the path at substantially the same time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A cable system for transmitting signals having frequency components of different frequencies spanning a predetermined frequency band, the cable system comprising:
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a head end facility;
a trunk operable to transmit signals along the trunk to and from the head end facility;
a tap in the trunk;
a feeder line connected at one end to the tap, an opposite end of the feeder line being for connection to an end user'"'"'s equipment;
the cable system defining a forward path for signals transmitted from the head end facility to the end user and a return path for signals transmitted from the end user to the head end facility;
at least one amplifier in the return path for amplifying signals transmitted from the end user to the head end facility, the amplifier(s) having diplex filter network(s) for separating the signals transmitted over the forward and return paths, the diplex filter network(s) causing a delay versus frequency characteristic within the predetermined frequency band for signals transmitted over the return path; and
at least one all-pass delay equalizer in the return path, wherein a delay versus frequency characteristic of the all-pass delay equalizer(s) within the predetermined frequency band is substantially a mirror image of that caused by the amplifier(s) with diplex filter network(s), such that all frequencies within the predetermined frequency band are delayed by substantially the same amount and hence all frequency components of the return signals occupying the predetermined frequency band arrive at the head end facility at substantially the same time. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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Specification