Abstract: A two-way cable network offering high-speed broadband communications delivered via virtual private networks over a multi-channel shared media system. Bi-directional transmission of packet to ATM cell based communications is established between a head end communication controller and a number of subscriber terminal units, whereby individual cells are prioritized and routed according to a virtual connection. Virtual connections are organized to support multiple virtual private networks in a shared media CATV system. The virtual private network to which a particular STU belongs is user selectable and has the flexibility of handling multi up/downstream channels with different MAC domains. The present invention can also handle non-ATM MAC domains via the same common ATM switch. To overcome the limited number of addresses inherent to common ATM switches, a mapping/remapping function is implemented in the port cards. Furthermore, downstream as well as upstream traffic are filtered at each STU.

Abstract: Each packet of the present invention is assigned a priority level. The current data packet flow rate is detected. This data packet flow rate is quantized into at least one data rate level. The current buffer circuit depth is determined as is the priority associated with the current data packet. The probability that the current packet is either dropped or used is determined by using the current data packet service flow rate, the data packet priority, and the current buffer circuit depth.

Abstract: A circuit for protecting a plurality of tip/ring SLIC cards during over current or over voltage conditions. A diode pair corresponding to each tip/ring pair provides positive voltage over voltage protection in a negative powering scheme. Two thyristors provide negative over voltage protection. Tip conductors of half of the SLICs connect to the cathode of one of the thyristors. The ring conductors corresponding to each of these tips connects to the cathode of the other, or second, thyristor. The remaining tips are connected to the cathode of the second thyristor. The rings corresponding to these remaining tips connect to the cathode of the first thyristor. This alternating connection of tips and rings provides twice the current capacity of a single thyristor, while cutting in half the potential holding current through either of the thyristors, thus increasing the likelihood of automatic return to normal operation following cessation of negative over voltage.

Abstract: A method for synchronizing transmitters within a communications network by utilizing wide-mode marshaling. Wide-mode marshaling increases the bandwidth dedicated to performing a marshaling process, thereby allowing a controller to quickly marshal the transmitters. Within a TDMA network, a TDMA frame includes a header portion and a multi-channel portion. Each of the transmitters within a TDMA network transmits during an assigned time-slot of the TDMA frame. To marshal a transmitter, the transmitter is requested to transmit a ranging signal to a central controller. If the ranging signal is received during the header portion of the TDMA frame, the controller can accurately detect the ranging signal. However, for longer propagation delays, the length of the header is insufficient. Wide-mode marshaling resolves this by silencing some or all of the transmitters to increase the bandwidth for receiving the ranging signal.

Abstract: A method and architecture that uses a ground-fault-circuit-interrupter (“GFCI”) proximate the tap to provide fault protection along a Low Power Network drop cable. The solution is single-ended and effective regardless of the input, impedance and type of termination equipment, such as an NIU, connected thereto. The GFCI may be incorporated into a single enclosure that includes a power passing tap and filter device, such as a low pass filter and a splitter. Application will typically be in a CATV network employing center core powering or Siamese powering. Ground fault protection is provided to personnel that contact an energized conductor of the drop cable who would therefore otherwise become an electrical path between the energized conductor and ground. A device providing this protection is typically mounted along a network cable proximate a tap point reasonably is inaccessible, except to service personnel.

Abstract: A full-wave rectifier, two resistors forming a voltage divider across the rectifier outputs and a capacitor in parallel with one of the resistors, provide an output across the capacitor that approximates the RMS equivalent of an input signal to the rectifier. The capacitance value may be selected to attenuate certain AC components without significantly affecting the accuracy of the RMS approximation. The shape of the input-signal-may be rectangular, trapezoidal, sinusoidal, triangular, random, constant DC, or a combination thereof, without affecting conversion accuracy. A DC voltage charge is maintained on the capacitor, which has been charged via the voltage divider, to a proportionally scaled equivalent of the RMS voltage of the input signal, through switched, non-symmetrical charge/discharge paths of the rectifier and the resistors.

Abstract: A method and system for equalizing the voltage of batteries in a battery string to a desired voltage. An equal string current is drawn from the batteries of the battery string and redistributed as a plurality of secondary currents to each battery depending upon the comparative voltage of the individual batteries. A larger secondary current is provided to batteries having a low voltage and a smaller secondary current is provided to batteries having a high voltage. A transformer is provided electrically connected to the battery string having an input winding connected to the battery string such that it receives an equal string current from each battery. The transformer has a plurality of output windings having an equal turn ratio, each output winding in parallel with a battery of the battery string, to provide a secondary charging current to a battery in the battery string.

Abstract: In a cable data system, several frequency division multiplexed upstream data signals on an individual cable can be selectively routed to frequency-selective band pass filters using a relay matrix between the filters and the cable. By appropriately controlling the relays, the upstream information can be split out to as many different filters that might be required to recover the frequency division multiplexed information. Cabling installation to a cable modem termination system is simplified and maintenance costs are reduced by carrying multiple signals on one cable.

Abstract: An enclosure for providing abundant convection cooling to components placed therein while protecting the components from environmental factors external to the enclosure. Wall, roof and floor structures form a compartment for containing the components; the wall structures define openings for air passage into the compartment through a bottom opening and out of the compartment through a top opening, as internally warmed air is moved by convection through the enclosure. Louvers in the walls prevent precipitation and other external environmental elements from entering the compartment through the bottom openings. An overhang eave of the roof has a lip that extends downwardly to prevent precipitation intrusion through the top opening or openings. Screen material internally affixed to the walls covers the openings to prevent entry of insects and small animals to the inside of the compartment.

Abstract: An RF choke is understood to be used in the cable television (“CATV”) systems to separate RF signals from the AC power signal, both of which initially co-exist when transmitted from the headend of the CATV system. The RF choke of the present invention, is modified by separating the predetermined number of turns from the winding adjacent to the “hot” (RF/AC) side of the RF choke in a CATV circuit. By evenly spreading these turns from each other with the purpose of reducing the series parasitic capacitance between the “hot” terminal and the rest of the choke. A useful parallel resonance at high frequency range in series with the rest of the choke is created. In addition, such a RF choke being connected (in shunt) to the RF signal path affects its performance to a much lesser degree than prior art chokes. Because of its reduced parasitic parameters, the choke of the present invention can be placed right at (or on) the AC/RF connector (terminal) of the PCB.

Abstract: A plurality of daisy-chained switching circuit cards are each coupled to a different active circuit card. Feed-through circuit cards are each coupled to spare circuit cards having substantially identical circuitry to the active circuit cards. The feed-through circuit cards are also daisy-chained with the switches on the switching circuit cards. The switching circuit cards can replace the feed-through circuit cards and the active circuit cards replace the spare circuit cards in order to vary the size of the spare groups (a group of spare circuit cards and active circuit cards) and also the quantity of the spare groups.

Abstract: A system and method for canceling both an echo signal and a spurious sinusoidal signal, such as a telephone dialtone or a carrier signal, from a return signal in a communications system involves producing a replica of the echo signal using an adaptive filter and producing a replica of the sinusoidal signal using an oscillator circuit. The replicas are subtracted from the return signal. The magnitude and phase of the sinusoidal signal are determined by generating a signal that is close in frequency to the expected frequency of the sinusoid and then correlating it to the return signal. The correlation produces a replica of the sinusoid.

Abstract: A method and apparatus for providing connection admission control (CAC) on a cable data system helps provide viable quality of service (QoS) capability on a cable data system. Cable data service is granted or denied to cable data service to said requesting subscriber based in part upon the determination of whether the available bandwidth is greater than, less than or equal to the bandwidth to be allocated to the requesting subscriber.

Abstract: In a cable data system, frequency division multiplexed upstream data traffic is first split for subsequent signal processing. In the course of performing an analog RF signal splitting operation, signal splitter output amplitude is decreased as an artifact of an RF signal splitter. A signal splitter indicator type that is used per signal splitter, provides an indication to the CMTS channel interface cards to control the amount of compensating gain required to restore the original signal to its original amplitude.

Abstract: In a method of calculating a variable spectral compression filter coefficient in a BTSC compatible stereo encoder from a feedback variable, a reciprocal value that is proportional to a reciprocal of the feedback variable is calculated. A lookup table is indexed using a preselected set of bits of the reciprocal value to generate at least one parameter of the filter coefficient function. An approximation of the compression filter coefficient is linearly interpolated based on the at least one parameter of the filter coefficient function. An apparatus that includes circuitry that calculates a variable spectral compression filter coefficient in a BTSC compatible stereo encoder from a feedback variable includes a reciprocal value circuit that calculates a proportional to a reciprocal value of the feedback variable.

Abstract: An apparatus (7) for switching from a first pilot signal and a second pilot signal on a system transporting a plurality of signals. A tuner (30) receives the signals and provides an output signal to a loop compensation circuit (26). The tuner includes a bandpass filter (22) for removing signals other than the selected pilot signal from the output of the tuner. The output of the bandpass filter is provided to a detector circuit (24, 25). The output of the detector is compared with a reference signal (28) by the loop compensation circuit (28). A microcontroller (39) sends a tuning command to the tuner which causes the tuner to switch from tuning to the first pilot signal to tuning to the second pilot signal and also sends a new reference voltage to the loop compensation circuit. Thus, if the input signal changes from analog to digital modulation on the pilot channel, the set-point, or target level of the reference signal, will automatically change to provide the correct value for operation of the circuit.

Abstract: A method for an integrated status transponder using the modulation of a return laser dithering signal. This invention provides a method for transmitting an optical node monitoring signal corresponding to error detection parameters over an optical network extending from a transmission site to a receiver. A stabilizing RF signal and the optical node monitoring signal based on error detection parameters are modulated to generate an “intelligent” integrated signal. The integrated signal and the principal RF signal used for various services are sent in conjunction over an optical network to a receiving site. The integrated and principal RF signals are received from the optical network by a receiver. Start and device identification bits can be used to identify the monitoring signal and to specify a downstream destination device.

Abstract: A battery voltage regulation circuit is provided for regulation the charging voltage of a battery. The system of the present invention includes a battery charger and a plurality of series connected batteries. Each of the plurality of series connected batteries are connected in parallel with a battery voltage regulator circuit. Each battery voltage regulator identifies excess battery current by using a voltage temperature compensation factor to compare the voltage of a battery to a reference voltage. A battery bypass circuit is used to remove excess battery current from a battery bath. In addition to being used in conjunction with a plurality of series connected batteries, the present invention may be used with a single charging battery to achieve the same results.