A tuner circuit and tuner

Abstract

The invention discloses a low noise block circuit and a low noise block. The low noise block circuit comprises a radio-frequency receiving module, a radio-frequency amplifying module, a radio-frequency power dividing module, a high-frequency filtering module, a single local oscillation frequency mixing module, a primary medium-frequency amplifying module, a shift switch, a secondary medium-frequency amplifying module and a plurality of output ports which are connected in sequence, wherein a low-frequency output port of the radio-frequency power-dividing module is unoccupied; and a high-frequency output port of the radio-frequency power-dividing module is connected with the high-frequency filtering module. A medium-frequency power dividing module is removed from the low noise block circuit, so that the wiring of a PCB (Printed Circuit Board) circuit is optimized; output of four paths of medium-frequency signals is realized; loss and mutual interference of the signals during transmission are lowered; the aim of wiring on a single panel of the low noise block is fulfilled; product performance is improved; the product Q value is increased; and the product material cost and manual operation cost are lowered.

Description

technical field [0001] The invention relates to the field of frequency reduction, in particular to a tuner circuit and a tuner. Background technique [0002] The working principle of satellite dish receiving satellite TV is to use the satellite dish to collect weak satellite signal and reflect the satellite signal to the LNB installed at the focal point of the dish antenna. Then, the tuner amplifies the concentrated signal and reduces the RF frequency to an intermediate frequency of about 1GHz to 2GHz, and then transmits it to the indoor receiver or digital output port group through the cable, and the receiver selects the channel to be watched in the signal , After being amplified and demodulated and restored to image and sound signals, they are input into the TV to play the program. [0003] According to the market area and customer needs, the LNB also uses a single local oscillator, dual polarization and multiple output products, such as circular polarization (ie Circular...

AI Technical Summary

Problems solved by technology

[0004] The disadvantages of the above two design structures are: 1) After the signal is processed by the first-stage intermediate frequency amplifier, it needs to be balanced by the intermediate frequency power divider, and then transmitted to the two sets of switching selector switches. During the signal transmission process, there are inter-stage losses and signal Interference; 2) After the signal is divided by the intermediate frequency, the signal needs to be output by connecting the PIN pin branch, that is, there are two PCBs combined to connect, this structure increases the product material cost and labor assembly cost; 3) The product has been processed many times, relatively external factors The stability caused by it is affected, and there are bad hidden dangers

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