China cell phone jammer of the specific model

Antenna switching circuit are generally integrated circuit and external components, such as the Motorola P7689 cell phone on the use of this approach, mainly by the U150, U151 and associated external components shown in Figure 4-4. The antenna switch circuit There are three main roles: for built-in antenna and external antenna ANTl EXT-ANT switch; for the transceiver to switch; for receipt of the letter 1800MHz, 900MHz, 1900MHz switch. External antenna connection from the bottom of the socket J600 provides the first 2 feet, which, INT-2 is prepared to receive 1800MHz band signal output, 1NT-3 is prepared to receive the 900MHz and 1900MHz frequency band signal output, RX275-DCS is the DCS band control signal, RX275- GSM-PCS is GSM, PCN band control signal, all from the CPU; TXIN for the transmit signal input, RF-V1 is the power switch for the transceiver, TXON allowed to transmit signals, RX-0N to receive the enable signal, FILTERED negative power. The working instruction of   cell phone jammer includes the warranty.
The antenna switch circuit has four control signals: U151 2-pin output signal control U150 ANTl within the antenna switch is turned to move transmitter or receiver circuit. U151 3-pin output signal control U150 in ANT2 antenna switch is turned to the outside or turning transmitter receiver circuit. RX275-DCS signal control U150 within the DCS band signal and the internal or external antenna is connected. RX275-GSM-PCS signal control U150 within the GSM, PCN-band signal and the internal or external antenna is connected. Some cell phone antenna circuit with a duplex filter (duplexer). Diplexer is a passive device. Internal filters including transmit and receive filters, which are band-pass filter. Duplexer has three ports, namely, public-ended antenna port, transmit output and receive input. Nokia 5110 cell phone on the use made of this form of the antenna circuit, the circuit shown in Figure 4-5. The customer orders   china cell phone jammer of the specific model.
Diplexer antenna ANT termination, RX side to receive the signal output, TX terminal is transmitting the signal input. In some phones, the antenna circuit using dual hearing device (Diplexer). Dual hearing device and the duplex filter is actually similar, the difference is that double hearing device in addition to separate transmit and receive signals, the signal will GSM900MHz and GSMl800MHz separately. Nokia 3310 cell phone uses a two-day hearing on the circuit device, the circuit shown in Figure 4-6. The   cell phone jammmerworkshop improves requirements of workshop management.  Foundation Stone Laying Ceremony of  cell phone jammmerJoint Venture
A conversion from the front and double-conversion receiver block diagram of the receiver can see, RXI / Q signals are output from the demodulation circuit, but the linear direct conversion receiver, the mixer output signal is RXVQ a . But no matter how the circuit structure change, they always have similarities: the signal from the antenna to the low noise amplifier, after frequency conversion unit, and then to the voice processing circuit. The inspection group wants to check the working instruction of  cell phone jammmer.
Antenna circuit is the first cell phone to receive the circuit-level circuit, is the last one transmitter circuit. Major role in the following points: First, the antenna into the air waves and high frequency current delivery to the receiver circuit. Second, separate transmit and receive signals sent, to avoid mutual interference between the two. Since GSM uses TDMA technology, cell phone, receiver and transmitter intermittent work, the antenna switch in the logic circuit under the control of access at the appropriate time slot to the receiver or transmitter channel. The third is used for internal and external antenna switching circuit. Fourth, for the dual-band or tri-band phone, the antenna circuit can also be GSM900MHz, GSMl800MHz or PCNl900MHz signal separately. Currently, cell phone antenna circuit main use of the following three forms, the following were introduced. The working instruction of  cell phone jammmerhas to be equipped in every working position in the workshop.