The RC filter circuit consists of a resistor (2) and a capacitor (3). It is possible to prevent the DC power supply from inverting and operating the overvoltage, the high harmonic voltage and the instantaneous overcurrent impact breakdown after all the signal protection terminals of the utility model are connected in series to all the signal output terminals of the electric tool post transmission disc. Utility model of the protection circuit, you can ensure that the letter box Hall element operating point stability. There are called inquiry plate, knife switch.Tool Post Encoder
The signal from the letter of the letter from the letter of the source code, the frame after the complex into a high-speed digital signal, in the frame multiple access, according to the system used in different microwave can be divided into quasi-synchronous digital series (PDH) and synchronization Digital series (SDH), and then into the pattern conversion part, the code conversion including line coding and line decoding, because the multiplex device from the serial code stream, usually including DC and low frequency components, and the transmission channel is DC , This eliminates the need for the DC component in the baseband signal, which is done by the encoder in the pattern transform.
The International Telecommunication Union (ITU) specifies that the transmission pattern is a high-density bipolar 3-zero substitution (HDB) code when the transmission rate is one, two, three times, and the transmission rate is quadratic , The transmission pattern is the symbol inverse code (CMI).Tool Post Encoder
The transmission code passes through the channel and enters the decoder, and becomes the non-return code suitable for the circuit processing. Using the clock extraction circuit from the transmission code to the clock, for the use of serial code stream processing. The scrambling code transforms the signal data stream into a pseudo-random sequence to eliminate the discrete spectral components in the data stream so that the signal power is evenly distributed within the allocated bandwidth. The serial / parallel transform converts the serial bit stream into parallel stream, The number of paths depends on the modulation used.
Error correction coding can reduce the bit error rate of the system. Gray code to complete the natural code to Gray code conversion, because the Gray code transmission bit error rate is low. Differential coding is used to solve the phase blur problem in carrier recovery. Since D / A converter can only carry out natural binary code to multi-level conversion, it is necessary to carry out gray / natural code transformation before D / A transformation, After the D / A conversion, the multi-bit symbols into multi-level signal, the role of cell equalizer is a multi-level signal into a narrow pulse to meet the transmission function of the input pulse requirements.Tool Post Encoder
And then enter the modulator for modulation, IF frequency is generally 70MHz or 140MHz, after the modulation of the IF signal through the delay equalization and IF amplification, sent to the letterbox mixer, the frequency has been modulated signal and the letter of the local signal After mixing the microwave has been modulated signal. And then through the one-way device, RF amplifier and shunt filter, in line with the output power and frequency requirements of the microwave signal has been transferred to the feeder system sent to the other side of the antenna.Tool Post Encoder