Loading patent…
Assignee3Com Corporation
InventorsAndrew L. Norrell, Scott A. Lery
Estimating the term…
A method of encoding data into a digital sequence to be transmitted over the DTN so as to cause the DTN's codec to generate a multiple modulus M-ary signal in a manner that will facilitate efficient data transmission and recovery (decoding) by the distant end receiver, even in the presence of robbed-bit signaling (RBS). The preferred embodiments provide an apparatus and method of converting blocks of binary data to a corresponding block of M.sub.1 -ary, M.sub.2 -ary, . . . , M.sub.n symbols using Multiple Modulus Conversion (MMC) to maximize the data rate, while minimizing the required Signal-to-Noise Ratio (SNR) to achieve a desired error rate, in a system having a transmitter connected to the DTN via direct digital access and a receiver connected over a conventional analog subscriber line. A subset of codec codewords is used to represent the M-ary signals. For each time slot (symbol time) one of M separate octets are selected for transmission by the encoder, and the encoder's output is sent through the DTN to a subscriber loop codec. The value of M can vary among the different time slots. The analog output of the codec corresponds to M-level, or M-ary pulse amplitude modulation, because each of the transmitted octets is converted to one of M analog voltages at the DTN's codec before being communicated over the subscriber loop.
A method for transmitting digital information from a data source having direct access to a digital telephone system for supplying binary codewords directly to the digital telephone system, to a receiver connected to said digital telephone system by an analog subscriber line, wherein the digital telephone system converts the binary codewords from the data source to analog voltage levels for transmission to the receiver, the method comprising the steps of:
A method of encoding information bits for transmission over a digital telephone system where an encoder has direct digital access to the digital telephone system, and wherein said digital telephone system appropriates bits during known bit-robbed rate time slots, comprising the steps of:
A method of decoding data symbols transmitted over a digital telephone system where an encoder has direct digital access to the digital telephone system for providing binary octets to the digital telephone system, and wherein said digital telephone system appropriates bits from said octets during known bit-robbed time intervals, and wherein said digital telephone system converts the octets to analog voltages, comprising the steps of:
A modulus converter for encoding information bits for transmission over a digital telephone system where an encoder has direct digital access to the digital telephone system, and wherein the digital telephone system appropriates bits during known bit-robbed rate time slots, comprising:
Dependencies are inferred from the claim text.