Compatibility mode pulse signal generation circuit and method
First Claim
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1. A network transmitter generating data frames of data for transmission on a network medium, the transmitter including a frame generation circuit comprising:
- a) a first physical layer circuit generating data frames including overhead bits and data bits and modulating such frames of data for transmission on a network medium using a first modulation scheme;
b) a second physical layer circuit generating data frames including overhead bits and data bits received from the media access layer circuit and modulating such frames of data for transmission on a network medium using a second modulation scheme; and
c) the first physical layer circuit and the second physical layer circuit being operatively coupled for generating a compatibility mode frame, by the second physical layer circuit, comprising the initial header overhead bits modulated using the first modulation scheme and the remainder of the frame modulated using the second modulation scheme;
wherein;
the first modulation scheme is a pulse position modulation scheme and the second physical layer circuit obtains pulse position data from the first physical layer circuit for the initial header overhead bits, andthe second modulation scheme is a quadrature amplitude modulation scheme and the second physical layer circuit generates pulses of a quadrature amplitude modulated carrier at times corresponding to the pulse position data to generate the initial header overhead bits.
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Abstract
A network transmitter for generating frames of data for transmission in a compatibility mode network including frames utilizing two modulation schemes is provided. The transmitter includes a first physical layer circuit generating frames utilizing a first modulation scheme and a second physical layer circuit generating frames utilizing a second modulation scheme. The second modulation circuit retrieves a compatibility mode header from the first physical layer circuit for generating compatibility mode frames.
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Citations
13 Claims
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1. A network transmitter generating data frames of data for transmission on a network medium, the transmitter including a frame generation circuit comprising:
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a) a first physical layer circuit generating data frames including overhead bits and data bits and modulating such frames of data for transmission on a network medium using a first modulation scheme; b) a second physical layer circuit generating data frames including overhead bits and data bits received from the media access layer circuit and modulating such frames of data for transmission on a network medium using a second modulation scheme; and c) the first physical layer circuit and the second physical layer circuit being operatively coupled for generating a compatibility mode frame, by the second physical layer circuit, comprising the initial header overhead bits modulated using the first modulation scheme and the remainder of the frame modulated using the second modulation scheme;
wherein;the first modulation scheme is a pulse position modulation scheme and the second physical layer circuit obtains pulse position data from the first physical layer circuit for the initial header overhead bits, and the second modulation scheme is a quadrature amplitude modulation scheme and the second physical layer circuit generates pulses of a quadrature amplitude modulated carrier at times corresponding to the pulse position data to generate the initial header overhead bits. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of transmitting data frames in a frame switched network including a first device capable of transmitting and receiving data frames utilizing pulse position modulation a plurality of second devices capable of transmitting and receiving data frames utilizing quadrature amplitude modulation, the method comprising:
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a) transmitting initial header overhead bits complying with the pulse position modulation scheme by transmitting pulses of a quadrature amplitude modulated carrier, utilizing a quadrature amplitude modulation physical layer circuit, in time durations complying with valid pulse positions; b) transmitting the remainder of the frame utilizing the quadrature amplitude modulation scheme; and c) scrambling at least a portion of the remainder of the frame modulated using quadrature amplitude modulation scheme to a scrambled format prior to modulation, the scrambled format providing for adequate bit transitions to limit electromagnetic noise outside a predefined transmission band; wherein a predetermined bit sequence from a media access layer initializes the scrambling, the predetermined bit sequence occurring after a preamble and before a data portion of the frame. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification