ABSTRACT
The mixer in communication engineering and radio technology, application is
very extensive, in modulation system, the input of baseband signal are
throughfrequency conversion into a high frequency modulated signal. In the
demodulation process, the received modulated high frequency signal afterfrequency
conversion, into intermediate frequency signals corresponding to.Especially in the
superheterodyne receiver, mixer is widely used, such as AMradio receiver will be
amplitude modulated signal 535KHZ- a 1605KHZ to become 465KHZ IF signal,
image signal television receiver will have a 870M48.5M to become 38MHZ of
intermediate frequency image signal. In mobile communication, a frequency and the
two frequency etc..
In the transmitter, in order to improve the stability of transmitting frequency, uses
the multistagetype transmitter. With a low frequency of the quartz crystal oscillator as
the main oscillator, generating the main oscillation signal of a frequency is verystable,
and then through the frequency plus or minus, multiply, divide intoradio frequency,
we must use a mixer circuit, such as converting TV transposer transceiver channel, the
uplink, downlink frequency in satellitecommunication transform, must be in the
mixer. Thus, mixing circuit is the key module of Applied Electronic Technology and
professional radio must master.
Key words anlog mixer; mixer circuit
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