Nonconformance of components of cell phonejammer is found

Cell phone service basis. Cell phone repair basic terminology. Those containing resistance, inductance and capacitance of the circuit from the AC of the obstacles. Three-point capacitance oscillator (also called reference is hereby oscillator). A self-excited oscillator. By the series capacitor and the inductor circuit and the positive feedback amplifier. Two series capacitor for oscillation circuit of the three endpoints, respectively, with the oscillating tube three pins connecting the name. Loop filter: the role with two low-pass filter: the output of phase detector attenuation of high frequency error components, in order to improve anti-interference performance; locked out of the loop when the loop to improve short-term memory, and rapid recovery signal. cell phone jammer adopts imported automatic surface mount system.
In the voltage-controlled oscillator circuit components used in frequency control devices as oscillators, VCO is a voltage-controlled oscillator for short. Is a modulated spectrum to a narrow main lobe, sidelobe fading fast, to meet the requirements of the GSM system a channel width of 200kHZ requirements, saving the modulation frequency resources. Encoding of digital communications. The main process is the voice, image and other analog signal sampling time intervals, so that discrete, while the value of the sample stratified according to the nearest rounded to quantify, while the sample values in a set of binary code to represent the sampling pulse amplitude . GSM system using frequency division multiplexing, the entire frequency band is divided into 124 pairs of carrier frequency, the carrier frequency interval is 200KHZ, duplex spacing of 45MHz. Thecell phone jammer has stable quality and performance with repair rate not more than 2%.
Band uplink (mobile to base station) to 890MHZ-9l5MHZ, downlink frequency band (base station to mobile station) is 935MHZ-960MHZ. In the downlink band number is n (n = l ~ 124) of the carrier frequency of the frequency can be Fu (n) = 890 +0.2 nMHz (upstream) or Fd (n) = 935 +0.2 nMHz = Fu (n) +45 MHZ (downstream). In each RF channel, GSM system uses TDMA access technologies, each carrier frequency is divided by time into a TDMA frame, the frame size is 4.6ms; each TDMA frame is divided into eight time slots, slot length of 557pS. Therefore, a carrier can have 8 cell phones simultaneously (a cell phone occupies a time slot). cell phone jammer selects Hitachi integrated circuit of high performance.
GSM cell phones transmit at the receiver using the same slot number, and start receiving the TDMA frame time relative to the launch delay the start time of the TDMA frame slot three time intervals, so that the time slot to receive launch separate, that the TDMA frame staggered to avoid the GSM launch at the same time due to simultaneous reception interference, so does not use GSM cell phones expensive duplex filter, thus reducing costs. GSM mobile communication system to meet the adjacent channel interference on the stringent requirements, the use of Gaussian minimum frequency shift key modulation (GMSK), the GMSK modulation, the modulation rate of 270833kbe, each time division multiple access TDMA frame occupies one slot to send a pulse cluster, the cluster pulse rate 33.86kbo. Reflow oven machining will be performed for cell phone jammer.
Modulation is the audio signal "attached" to the high-frequency oscillation, and with the audio signal to control the high-frequency oscillation parameters. Remove from the modulated wave audio modulation signal is called demodulation. One kind can convert direct current with a certain frequency AC signal output circuit combination. Refers to the total integration parameter or distributed parameter circuit reactance components of the composition. Is a realization of phase-lock automatic control system. It is generally the phase detector, loop filter, voltage controlled oscillators and other components. Also known as "digital to analog converter", referred to as "DAC." Will be converted to its corresponding digital analog circuit. 825~960MHz is one of working frequency of cell phone jammer.