Abstract: In accordance with the present invention, a driver chip is provided for transmitting optical signals over an optical fiber. The driver chip includes, in combination, a tapped delay equalizer, an amplifier and control circuitry. Operationally, the tapped delay equalizer modifies an input digital signal to create a compensated signal by compensating for anticipated impairments and distortions introduced during signal transmission. The amplifier then receives the compensated signal to provide gain and bias in order to establish a proper operating point for an E/O device. The control circuitry is interconnected with the tapped delay equalizer and with the amplifier to establish and control tap weights for the tapped delay equalizer to compensate for electrical and optical bandwidth limitations, along with optical dispersion effects.

Abstract: Methodologies for designing and assembling an analog Nyquist filter require a filter unit which includes a low pass filter in cascade with at least one tapped delay filter. A Signal Generator is used to generate a test pattern for input into the filter unit in order to create a reaction signal from the filter unit. This reaction signal is then compared with a desired Nyquist response. Based on this comparison, amplifier gains for taps in the tapped delay filter are weighted to establish a transfer function in the filter unit. In operation the transfer function shapes analog input signals with the desired Nyquist response for use as an output from the Nyquist filter.

Abstract: An analog signal processing device for equalizing a low pass filter to create a Nyquist filter in accordance with the present invention includes a low pass filter for passing a predetermined bandwidth, and a tapped delay filter connected with the low pass filter to create the Nyquist filter. In more detail, the tapped delay filter is used to sample an input analog signal having a predetermined symbol rate. The samples from the input signal are then respectively weighted to establish a system transfer function for the Nyquist filter. The purpose here is to minimize both inter-symbol interference and transmission bandwidth. A decision circuit can be provided to convert the input signal into a desired data format for creation of an output signal to be transmitted by the data transmission system. Also, the Nyquist filter can be selectively evaluated as an “eye diagram” and the system transfer function appropriately adjusted accordingly.

Abstract: Methodologies for designing and assembling an analog Nyquist filter require a filter unit which includes a low pass filter in cascade with at least one tapped delay filter. A Signal Generator is used to generate a test pattern for input into the filter unit in order to create a reaction signal from the filter unit. This reaction signal is then compared with a desired Nyquist response. Based on this comparison, amplifier gains for taps in the tapped delay filter are weighted to establish a transfer function in the filter unit. In operation the transfer function shapes analog input signals with the desired Nyquist response for use as an output from the Nyquist filter.

Abstract: A system for transporting a plurality of analog and/or digital signals over an optical fiber can include one or more master modems for modulating digital signals and/or RF inserters modulating video signals. The RF signals from the modem(s)/RF inserters are up-converted resulting in frequency bands that are non-overlapping and are spaced apart within a single sub-octave. The sub-octave signal is then converted into an optical signal and directed onto an end of an optical fiber. At the downstream end of the optical fiber, the received optical signal is converted to an RF signal at an optical receiver. The RF signal is then filtered, down-converted and directed to a selected coaxial distribution unit. From the coaxial distribution unit, the RF signal is demodulated, e.g. at a slave modem, to recover the initial analog and/or digital signal.

Abstract: A system for transporting a plurality of digital signals (i.e. “n” digital signals) over an optical fiber includes a plurality of modems for modulating each digital signal on a respective analog signal. Each resulting RF signal is processed by a corresponding up-convertor, which includes a mixer and local oscillator, to produce a frequency band which can be a double sideband or single sideband of the modulated signal. The resulting frequency bands output by the up-convertors are non-overlapping and are spaced apart within a single sub-octave. An RF combiner combines the frequency bands and the combined RF signal is converted into an optical signal by an optical transmitter that outputs to an optical fiber. An optical receiver converts the optical signal from the fiber to an RF signal that is directed to an RF splitter. Signal fractions from the splitter are filtered, down-converted and demodulated to recover the initial digital signals.

Abstract: A system and method are provided for transmitting multi-octave telecommunications signals, as sub-octave signals, on an optical fiber. Using different modems, digital signals are modulated onto respective radio frequency (RF) carriers. In detail, the resultant RF signals (fn) are all within a same lower frequency band. At least one fn is a multi-octave signal. A frequency changer switches each fn (possibly multi-octave) from the lower frequency band to an upper frequency band, where they avoid overlapping each other, and where they are each established as a sub-octave signal (f?n). A combiner then groups the individual sub-octave signals (f?n) into a single sub-octave signal (f?). Further, an electrical/optical converter creates an optical signal of wavelength (?) for transmitting the combined sub-octave signal (f?) over the optical fiber.

Abstract: A system for regulating the signal strengths of a plurality of Radio Frequency (RF) signals to reduce signal degradation includes a plurality of controllers. Each controller is operably positioned upstream of an electrical-to-optical converter which generates an optical signal for transmission over a fiber optic transmission path. Each controller functions to detect and identify RF signals whose strength exceeds a maximum value and immediately attenuate the RF signal to prevent the transmission path from being jammed by the signal. Each controller also performs a signal leveling function by sampling signal strength, over time, and uses moving window averaging or some other moving window statistic to level the RF signal. Structurally, each controller includes a detector, a signal attenuator and a signal amplifier that are operationally positioned along a signal path extending from a controller input port to a controller output port and are operationally connected to a processor.

Abstract: A system for transmitting an optical signal over a fiber optic includes a terminal for generating the optical signal. Due to its modulation, the optical signal includes a carrier having a wavelength “?”, with an upper sideband and a lower sideband. A tuner is connected with the terminal to adjust the wavelength “?” of the carrier of the optical signal relative to a band pass filter. The purpose here is two-fold. For one, this adjustment eliminates a sideband of the optical signal, to avoid fading, and it suppresses the carrier of the optical signal, to enhance the OMI while maintaining the linearity of the signal.

Abstract: A system for transporting a plurality of digital data streams over an optical fiber can include a plurality of upstream quadrature amplitude modulation (QAM) modems. Each QAM modem encodes a digital stream onto a carrier signal by modulating both the amplitude and the phase of the carrier signal. Each QAM modem also up-shifts the signal frequency, with each up-shifted signal having a frequency within a single sub-octave frequency band to suppress composite second order distortions that can occur during optical transport. The QAM signals are combined and converted to an optical signal that is transmitted over an optical fiber to a receiver. To convert the signal, a voltage source is connected with an electro-absorption modulator to provide a bias voltage for altering an optical power of the optical signal with a DC offset. The DC offset minimizes third order distortions of signals transmitted on the fiber optic.

Abstract: A system for transporting a plurality of relatively low-frequency information signals over an optical fiber can include a plurality of transmitters. Each transmitter receives one of the relatively low-frequency information signals as an input, processes the input signal, and outputs an up-shifted (i.e. relatively high frequency) signal that has a suppressed sideband to reduce transmission power requirements. Sideband suppression is accomplished using a technique in which a first component of the input signal is shifted in phase by 180 degrees and summed with a second, in-phase signal component. The signals output from the transmitters are then frequency stacked and the resulting signal is converted to an optical signal for transmission over an optical fiber. The up-shifted signals output from the transmitters have frequencies within a single sub-octave frequency band to reduce the adverse effects of composite second order distortions that can occur during optical transport of the information signals.

Abstract: A system and method for transmitting telecommunication signals through a fiber optic, with suppression of second and third order distortions, requires a signal processor for generating a sub-octave broadband signal. An Electro-Absorption Modulator (EAM) is provided to modulate the sub-octave broadband signal into an optical signal ?. And, a DC offset voltage is used to alter optical output power in the optical signal ?. The sub-octave broadband transmission then minimizes second order distortions of the optical signal ?, and the DC offset minimizes third order distortions when the optical signal ? is transmitted on the fiber optic.

Abstract: A system for transporting a plurality of analog and/or digital signals over an optical fiber can include one or more master modems for modulating digital signals and/or RF inserters modulating video signals. The RF signals from the modem(s)/RF inserters are up-converted resulting in frequency bands that are non-overlapping and are spaced apart within a single sub-octave. The sub-octave signal is then converted into an optical signal and directed onto an end of an optical fiber. At the downstream end of the optical fiber, the received optical signal is converted to an RF signal at an optical receiver. The RF signal is then filtered, down-converted and directed to a selected coaxial distribution unit. From the coaxial distribution unit, the RF signal is demodulated, e.g. at a slave modem, to recover the initial analog and/or digital signal.

Abstract: A system for transporting a plurality of digital signals (i.e. “n” digital signals) over an optical fiber includes a plurality of modems for modulating each digital signal on a respective analog signal. Each resulting RF signal is processed by a corresponding up-convertor, which includes a mixer and local oscillator, to produce a frequency band which can be a double sideband or single sideband of the modulated signal. The resulting frequency bands output by the up-convertors are non-overlapping and are spaced apart within a single sub-octave. An RF combiner combines the frequency bands and the combined RF signal is converted into an optical signal by an optical transmitter that outputs to an optical fiber. An optical receiver converts the optical signal from the fiber to an RF signal that is directed to an RF splitter. Signal fractions from the splitter are filtered, down-converted and demodulated to recover the initial digital signals.

Abstract: A system for transporting a plurality of digital signals includes a head-end unit for routing each digital signal to a particular modem, according to address information in the signal. At its respective modem, each digital signal is mixed for further transmission on a unique, modem-specific, radio frequency (fn) that is predisposed for a sub-octave transmission. A first converter then “stacks” a plurality of the different digital signals onto a common wavelength (?) for transmission as an optical signal over an optical fiber. At the receive end of the optical fiber, a second converter “de-stacks” the plurality of digital signals, and segregates them according to their respective unique radio frequency (fn). A distribution unit then directs each unique radio frequency signal to an addressed node for further transmission over a secondary network.

Abstract: A system and method for enabling multiple sub-octave band transmissions with reduced second order distortions is provided. For this method, first and second sub-octave bands are established. The second sub-octave band is spaced from the first sub-octave band by a non-transmission band. Digital signals are modulated onto RF carrier frequencies in the first and second band to produce first band RF signals and second band RF signals. The first and second band signals are converted into one or more light beams and transmitted over a fiber optic cable. After transmission, an optical receiver reconverts the light beam into an RF signal. Second order distortions outside a selected sub-octave band can be filtered from RF signal and a tuner used to tune in a selected carrier frequency. A receive modem can then be used to demodulate the tuned carrier frequency for receipt of its respective digital signal.

Abstract: A passive optical network for transmitting digital signals incorporates sub-octave filters for the removal of distortions introduced into the signals as they are transmitted over the fiber optic cable of the network. Stated differently, second order distortions that result when the light beam carrying the digital signals is passed through a fiber optic cable are removed by the sub-octave filter. Further, the employment of another passive optical network on the same fiber optic cable with the present network is provided for. And, considerations for ensuring the compatibility of upstream and downstream transmission frequencies with the sub-octave filters are disclosed.

Abstract: A system and method are provided for controlling the transmission of RF signals that are to be carried as optical signals over an optical fiber network. Operationally, the optical signals are transmitted as “bursts” in accordance with a standard protocol. For the present invention, transmission control requires an ON/OFF control that incorporates a time delay. Specifically, a “burst” of signals (RF/optical) is initiated when power in the RF input signal passes a predetermined threshold. After an established turn-on time that is set by the time delay, the ON/OFF control activates a laser diode for transmission of the “burst.” Further, the present invention provides control for constant optical output power from the laser diode. Importantly, the laser diode is OFF when a “burst” is not being transmitted.

Abstract: A point-to-multipoint optical communication network includes a fiber optic cable, and a single photodiode for optical/electrical conversion at the upstream end of the cable. On the other hand, an “n” number of electrical/optical up-converters are connected between an “n” number of downstream points and the downstream end of the cable. Within this arrangement, radio frequency signals “fn” from respective “n” different downstream points are impressed onto respective wavelengths “?n”. The resultant optical signals “?n” can then be simultaneously transmitted upstream over the fiber optic cable, and passed through the photodiode for optical/electrical conversion and transmission to an upstream point, according to “fn”. For downstream communications, a single transmitter and a single wavelength ? can be used to transmit all fn signals.

Abstract: A system for transporting a plurality of digital signals includes a head-end unit for routing each digital signal to a particular modem, according to address information in the signal. At its respective modem, each digital signal is mixed for further transmission on a unique, modem-specific, radio frequency (fn) that is predisposed for a sub-octave transmission. A first converter then “stacks” a plurality of the different digital signals onto a common wavelength (?) for transmission as an optical signal over an optical fiber. At the receive end of the optical fiber, a second converter “de-stacks” the plurality of digital signals, and segregates them according to their respective unique radio frequency (fn). A distribution unit then directs each unique radio frequency signal to an addressed node for further transmission over a secondary network.