The output frequencies are controlled digitally with digital bits of different lengths applied to delay cells. Further, a four-bit controlled DCO is implemented with the second approach. Three, five and seven-stage DCO is implemented with the first approach. Two design approaches for new delay cell are presented. New Digitally Controlled Oscillator (DCO) structures based on delay cells with novel three-transistor NAND gate are presented in this paper. Manoj Kumar, Sandeep K Arya and Sujata Pandey Article Price : Rs.50ĭigitally Controlled Oscillator with Novel Variable The results obtained showed that the configuration of FM radio transmitters in Niger State does not give optimum coverage of the State.
The parameters obtained were used to determine the coverage areas of the two FM radio signals studied in Niger State. The longitude, latitude, altitude and also distance from the reference point (i.e., location of the transmitting antenna) were measured at every location using a handheld Global Positioning System (GPS) receiver. A Digital Signal Level Meter, GE-5499, covering the signal range of 30-120 dBµV, was used to measure the signals. In this work, measurement of electric field strength of Frequency Modulated (FM) radio signals from Crystal FM, Minna, on 91.2 MHz and Power FM, Bida, on 100.5 MHz in Niger State Nigeria, was carried out in all the 25 Local Government Areas of the state. The electric field strength of radio signals decreases with increase in distance from the transmitting antenna. These radio signals are affected by the electrical parameters of the ground, curvature of the earth surface, height of the antenna above earth’s surface and weather conditions in the troposphere. In the VHF band (30 MHz-300 MHz), radio propagation is usually by space waves, which consist of direct wave and ground-reflected wave. M O Ajewole, O D Oyedum, A T Adediji, J O Eichie and A S Moses Spatial Coverage of FM Radio Transmitters in Niger State, Nigeria
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