Internet Over TV Bandwidth Prepared by: Ahmad Antari Izzeddin Habbazi Ayham Odeh Dr.Ahmed masri
Outlines Introduction. Digital Dividend. Oscillator Design. Band Pass Filter Design. Power Amplifier Design. SWOT Analysis. Future.
Introduction A several research work have been done on Wireless Communication in the past few years and many applications have been developed. Our main target is to down verge the higher frequency (Wi-Fi signals) into the low frequency (TV band). To achieve that we have to design a local oscillator with carrier frequency (1.6-2.05 GHz).
IOTV It is a project that aims to transmit Internet wirelessly over TV band. In order to cover rural and remote areas.
Definitions Licensed band : No one can transmit over this band only the authorized one. Unlicensed band : Anyone can transmit over this band under strict specifications. White spaces : Frequencies allocated to broadcast services but are not used. Secondary users over licensed band
Digital Dividend Is now available for television systems (up to six signals, depending on the coding and modulation techniques). The digital dividend band was between 200 MHz and 1 GHz. lower frequencies facilitate provision of coverage and thus to achieve an optimal balance between transmission capacity and operational range. This would mean that less Infrastructure would be required to provide wider mobile coverage, all resulting in lower costs for communication services, especially in rural areas.
previous work The system was not stable The final value of frequency we reached was 1.3GHz. The circuit was implemented as PCB.
Oscillator It converts dc power supply to the ac power in the load. It is considered a signal source for frequency conversion and carrier generation.
Design Circuit for a two-port transistor oscillator.
Active device Allowing easy integration with transistor amplifiers and mixers, while diode devices are less compatible. Transistor oscillator circuit is much more flexible than a diode source. Transistor oscillators usually allow more control of the frequency of oscillation, temperature stability, and output noise than do diode sources.
Design Steps: Check if the transistor is potentially unstable (K < 1) if the device is not potentially unstable: Use feedback element like an capacitor to make the device unstable. Change the configuration to common-gate or common-base. Check if the oscillator circuit is stable: This can be attained by making S11, S22 and delta less than one, but Mu and stab factor(k) more than one. Choosing the reactive elements values by achieving the stability conditions at the desired frequency .
Negative Resistance Oscillator
ADS Software Advanced Design System (ADS) is an electronic design. It provides an integrated design environment to designers. ADS supports every step of the design process.
Oscillator cct. In ADS Software `
Layout
Problems We faced
We faced two main problems which are :- 1) Frequency harmonics existence. We solve this problem by using band pass filter. 2) The output power was small. We solve it by using power amplifier.
Band Pass Filter cct. In ADS
Power Amplifier
The whole system block diagram
Application The main topology is to increase the Wi-Fi range by adding the adaptor which is a transceiver between the routers in home and the end devices
SWOT Analysis
S W O T There is no 3G technology in Palestine. TRENGTHS W EAKNESSES There is no 3G technology in Palestine. The results of this phase are valuable resource for researchers, companies...etc Competitive. the hardware & software implementation of the oscillator does not give the same results of because there are some losses. the interference with nearby signals. Internal factors O T HREATS PPORTUNITIES The absence of broadband internet services in rural areas. Switching to digital TV, this will free up more spectrum to be used. Absence of rules and regulations about channels allocation. Occupation. External factors Positive Negative
Future This topology shows the future of the project as an alternative to the 3G We must book a frequency in TV band as a licensed band. This system is cheaper than 3G and it will use less infrastructure.
Thank You Any Question?