Superposed quadrature modulated baseband signal processor
AssigneeCanadian Patents and Development Limited-Societe Canadienne des Brevets et d'Exploitation Limitee
InventorsJongsoo Seo, Kamilo Feher
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Abstract
A signal processor for providing a continuous raised cosine output signal having no jitter or intersymbol-interference and with controllable main and side lobes. An NRZ input signal is converted to a double interval raised cosine pulse signal having an amplitude normalized to 1.0. Another single interval raised cosine pulse signal having a peak amplitude (A-1) is superposed with the former raised cosine pulse to provide the output signal.
Claims20
A signal processor comprising:
- (a) means for converting an NRZ input signal to a double interval raised cosine pulse having a peak amplitude normalized to 1.0,
- (b) means for superposing another weighted single interval raised cosine pulse having a peak amplitude (A-1) with the former raised cosine pulse to provide a continuous output signal, of a form related to the NRZ input signal,
- in which the converting and superposing means are comprised of:
- (i) means for detecting the binary values of each pair of consecutive bits of the NRZ input signal;
- (ii) means for generating an output signal having the function Y.sub.1 =-A(1-A) cos (2.pi.t/T) if the pair of bits are -1, -1;
- (iii) means for generating an output signal having the function Y.sub.2 =-cos (.pi.t/T) if the pair of bits are 1, -1;
- (iv) means for generating an output signal having the function Y.sub.3 =cos (.pi.t/T) if the pair of bits are -1, 1 and
- (v) means for generating an output signal having the function Y.sub.4 =A+(1-A) cos (2.pi.t/T) if the pair of bits are 1,1,
- where T is the NRZ input signal symbol duration, and A is the amplitude parameter of the processor,
- the output signals being continuous.
A signal process for a modulator comprising:
- (a) means for detecting the binary values of each pair of consecutive bits of an NRZ input signal,
- (b) means for generating signals having waveshapes according to the functions y.sub.1 =-A-(1-A) cos (2.pi.t/T), y.sub.2 =-cos (.pi.t/T), y.sub.3 =cos (.pi.t/T) and y.sub.4 =A+(1-A) cos (2t/T), where T is the input signal symbol duration, and A is an amplitude parameter,
- (c) means for switching said y.sub.1, y.sub.2, y.sub.3 and y.sub.4 signals to an output transmission path to form a continuous signal according to the following table:
- ______________________________________ 1st NRZ bit Following NRZ bit Output Signal ______________________________________ -1 -1 y.sub.1 1 -1 y.sub.2 -1 1 y.sub.3 1 1 y.sub.4 ______________________________________
A signal processor comprising:
- (a) means for detecting the binary values of each pair of consecutive bits of a digital signal,
- (b) means for generating a continuous output signal having a waveshape dependent on the binary values of each pair of said bits,
- in which said continuous output signal is formed of waveshapes according to the functions Y.sub.1 =-A-(1-A) cos (2.pi.t/T), Y.sub.2 =-cos (.pi.t/T), Y.sub.3 =cos (.pi.t/T) and Y.sub.4 =A+(1-A) cos (2.pi.t/T) where T is the input signal symbol duration, and A is an amplitude parameter, which follow in smooth sequence according to the following table:
- ______________________________________ 1st NRZ bit Following NRZ bit Output Signal ______________________________________ -1 -1 Y.sub.1 1 -1 Y.sub.2 -1 1 Y.sub.3 1 1 Y.sub.4 ______________________________________
Dependencies are inferred from the claim text.