| 摘要 |
The invention pertains to the communication systems with amplitude modulation (AM) of finite length pulses. The baseband filter system's block diagram offered is shown fig. 10 where the filter of transmitter as well as filter of receiver is set as a chain of equal links (RLC) connected in series. The outputs of said links are connected to an adder (?) through the analogue dividers (xg1, ..., xgk) where said dividers determine the tap weights of links, but pulse characteristics of links are orthogonal with each other (for example, Laguerre's polynomials) or biorthogonal with some other linear independent function's class, as for example, biorthogonal with Bessel's functions J2k-1(t), in time interval [0, (). Here is also offered a baseband filter synthesis method for communication system with intersymbol interference prevention, which is specific because it minimizes the difference functionals when summarizing the base chain links reactions according to tap weights. Besides, standard mean deviation of step response from half infinite sum is used as difference functional in transmitter filter synthesis. Said half infinite sum is acquired by adding values of square root raised cosine or its analogue function with delay step of argument, which equals to input pulse length. Minimization functional for synthesis of receiver's filter is formed by multiplication of two differences, where one of the differences is mean standard deviation of all filter system's step response from Heaviside step function at the points following each other with a period equal to input pulse length, but other difference is mean standard deviation of filter system's amplitude spectrum from amplitude spectrum of afore mentioned sum's time derivative.
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