Alternative Approach to Use of Pulse Width Modulation

There are many requirements placed on the new generation of micro and macro robots, such as communication between robots, allowing coordinated actions, cognitive capabilities, smart behavior, etc. A pulse-width modulation (PWM) is widely used in different areas of control systems, such as robotics, industrial process control, power control systems, etc. A PWM circuit converts a DC voltage into a series of pulses, so that the pulse duration is directly proportional to the value of DC voltage. In spite of wide use of PWM, there are disadvantages of using PWM such as the possibility of generating radio-frequency interferences (RFI). In addition, when control by frequency modulation (FM) is desired the ON-period of PWM pulse is kept constant, but the frequency is varied in order to bring regulation. It is difficult to make the ON-period below a certain time duration. When the limit is reached, control by a PWM becomes impossible. The value of a minimum ON-period depends on the transistor switch. Due to the varying pulse width, PWM is unusable for time division multiplexing (TDM). Usually these problems are encountered when a 555 IC timer is employed as PWM. In this paper we propose two alternative methods for PWM.