Design And Facture Of The Circuit Disturbing Mobile Signal

The rapid development of the mobile communication brings greatconvenience to the people's life. However, with the wider and wider usage ofthe mobile phone, many problems which can'be ignored emerge. They mainlyare:1. new insecurity factors; it brings potentialinsecurity to the manufacturing of companies;2. new leakage channels; it becomes a menace forthe information security;3. new noise pollution source; it interrupts people'snormal work sequence;4. new criminal methods; it affects the stability ofthe society.So it's great urgency for the information security department to researchand develop a device to interrupt or shield the mobile signal. This paper isdiscussing how to realize the very interruption by using electronic circuits.The mobile signal interrupt-meter designed in this paper can transmit theinterrupting signal whose frequency is the same as what the mobile phonereceives. The interrupting signal can overwhelm all the mobile phone's receivesignal in coverage area, so it closes off all the contact with outside and disablethe communication function of mobile phones. So this interrupt-meter canprevent the information's leakage of the meeting place by mobile phone andthen guarantee the meeting order. When the temperature of environment varies,the center frequencies of the frequency band can keep stable by CPU'srevision timely. Meanwhile the interrupt-meter must has the characteristic suchas:1. it doesn't interrupt the signal on the base station of CHINA MOBILE and CHINA UNICOM.2. the frequencies of the output signal are stable and adaptive.3. the four frequency bands can scan independently.4. it's must be easy to produce and debug.5. the performance of the product must be stable.At the beginning of this paper, the history of the cellular mobile systemand some technologies adopted in it are simply introduced. Then introducehow to interrupt the mobile signal in theory and the frequency bands of HINAMOBILE, CHINA UNICOM, and CHINA TELECOM PAS Personal AccessPhone System), and at same time list the design aim of the mobile signalinterrupt-meter.This paper emphasize on the transmit circuit and the manufacturing of theRF PCB of this interrupt-meter.In the second chapter of this paper, we describe the main parts of thecircuit generally. The mobile signal interrupt-meter mainly consists of: CUPsequence controlling circuit, D/A transition circuit, frequency samplingcontrolling circuit, 200 KHz scanning saw-tooth wave generator, 900 MHzhigh frequency VCO (Voltage Controlling Oscillator), 1800 MHz highfrequency VCO, 900 M power amplifier, 1800 M power amplifier, antenna,and regulated power supply.Then in the third chapter, we describe the transmission circuit of themobile signal interrupt-meter in detail, for the design of this part stand or fallis directly relate to whether it can interrupting the mobile signal or not. Thetransmission circuit of the interrupt-meter mainly consists of high frequencyoscillator, power amplifier, microstrip and antenna. The high frequencyoscillator produce the needed frequency by inputting the harmonic voltagegenerated by the RC circuit to VCO. The power of the output from VCO isvery low, so it need to be amplified by power amplifier. In order to accomplishhigh efficient transmission, microstrip is usually used in RF (high frequency)circuits. The output voltage from the amplifier is transmitted to the antenna bymicrostrip, and then the antenna radiates the signal around.In the fourth chapter it is the basic circuit of the mobile signal...