I.V. Ryabov - Dr.Sci. (Eng.), Associate Prof., Mari State Technical University. E-mail: ryabov22@mail.ru P.M. Yuriev - Postgraduate, Mari State Technical University. E-mail: YurevPM@marstu.net S.N. Tolmachev - Postgraduate, Mari State Technical University

The methods of the increase in operation speed of digital computing synthesizers are considered in the article. New structures of digital frequency synthesizers and digital computing synthesizers having advanced features in comparison with known synthesizers are suggested. For the last decades due to the development of microelectronics and computer engineering the rapid development of a comparatively new direction of signal formation based on the application of the direct digital synthesis method is observed. With the help of ADC and LPF the signals of the required form ("harmonic", "saw-tooth", "triangle") as well as amplitudes, phases and frequencies are received at the output of the digital synthesizers. Meeting the following conditions: high stability of the reference generator frequency, small jitter-factor of the reference generator; high digit capacity of a phase calculator and good dynamic characteristics of outlet ADC we can receive an output signal with unique characteristics, unattainable with other methods of signal and frequency synthesis. Advantages of DDS: extreme rapid frequency tuning, minute frequency grid pitch; good repetition of synthesizer parameters when replicating, convenience of DDS control with the help of digital interface. Disadvantages of DDS: high requirements for operation speed, especially it concerns the phase calculator and code converter (that are constructed on the basis of tabular procedure), as well as for dynamic and static modes of operation of ADC.