Transmission system using transmitter with phase modulator and frequency multiplier
First Claim
1. A transmission system including a transmitter for transmitting to a receiver via a transmission medium a carrier wave which is phase modulated by a sequence of digital symbols, the phase modulation being in accordance with a transmitter output constellation, said transmission system comprising:
- an oscillator for generating a local carrier wave;
a phase modulator for modulating and creating the local carrier wave with said sequence of digital symbols in accordance with an additional constellation of phase states, the number of phase states in said additional constellation being greater than the number of phase states in said output constellation;
phase states of said additional constellation of phase states defining corresponding phase states of said output constellation of phase states;
whereby a desired new output constellation phase state is produced by creating a new additional constellation phase state; and
where said production of said new output constellation phase state requires less transient phase states of said output constellation than if said additional constellation did not have a greater number of phase states than said output constellation.
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Abstract
A transmission system for transmitting digital symbols by modulation according to a phase constellation includes a transmitter having a phase modulator and a frequency multiplier in cascade for producing a modulated signal having a desired transmission frequency. To prevent degradation of the bit error rate of such signal, the phase constellation at the input of the phase modulator has at least one additional phase state relative to the phase constellation at the output of the frequency multiplier. Advantageously, the number of phase states of the constellation at the input of the phase modulator is N times the number of phase states of the constellation at the output of the frequency multiplier, where N is the frequency multiplication factor.
138 Citations
12 Claims
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1. A transmission system including a transmitter for transmitting to a receiver via a transmission medium a carrier wave which is phase modulated by a sequence of digital symbols, the phase modulation being in accordance with a transmitter output constellation, said transmission system comprising:
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an oscillator for generating a local carrier wave; a phase modulator for modulating and creating the local carrier wave with said sequence of digital symbols in accordance with an additional constellation of phase states, the number of phase states in said additional constellation being greater than the number of phase states in said output constellation; phase states of said additional constellation of phase states defining corresponding phase states of said output constellation of phase states; whereby a desired new output constellation phase state is produced by creating a new additional constellation phase state; and where said production of said new output constellation phase state requires less transient phase states of said output constellation than if said additional constellation did not have a greater number of phase states than said output constellation. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A transmitter for transmitting a carrier wave which is phase modulated by a sequence of digital symbols, the phase modulation being in accordance with a transmitter output constellation having a predetermined number of phase states;
- said transmitter comprising;
an oscillator for generating a local carrier wave; a phase modulator for modulating the local carrier wave with said sequence of digital symbols in accordance with an additional constellation of phase states, the number of phase states in said additional constellation being greater than the number of phase states in said output constellation; phase states of said additional constellation of phase states defining corresponding phase states of said output constellation of phase states; whereby a desired new output constellation phase state is produced by creating a new additional constellation phase state; and where said production of said new output constellation phase state requires less transient phase states of said output constellation than if said additional constellation did not have a greater number of phase states than said output constellation. - View Dependent Claims (9, 10, 11, 12)
- said transmitter comprising;
Specification