Youncen
Member level 2
i/q mixer
new question:
than in the transimiter, quadrature structure is still used,why is it used , is the i/q mixer be modulated with the same signal or different two signals ???
and I have this question
for qam or qpsk etc........
when a I/Q(different) modulated signal s1*sin(w*f1)+s2*cos(w*f1) generated by upconverter,when it travel trought I/q downconverter,the original two different signal will be converted to two different complex signal s1*sin(w*f2)+s1*cos(w*f2) and s2*sin(w*f2)+s2*cos(w*f2),f2 can be equal to f1 if it is a direct convertion receiver, these two if signal have carrier overlap not orthogonal~~~~~,how can it be rendered or demodulated?
the original question:
why the quadrature mixer structure is used especially in some low if receiver, just for the convience of adding a polyphase filter to reject image?
got it! thanks to 2,3,4
new question:
than in the transimiter, quadrature structure is still used,why is it used , is the i/q mixer be modulated with the same signal or different two signals ???
and I have this question
for qam or qpsk etc........
when a I/Q(different) modulated signal s1*sin(w*f1)+s2*cos(w*f1) generated by upconverter,when it travel trought I/q downconverter,the original two different signal will be converted to two different complex signal s1*sin(w*f2)+s1*cos(w*f2) and s2*sin(w*f2)+s2*cos(w*f2),f2 can be equal to f1 if it is a direct convertion receiver, these two if signal have carrier overlap not orthogonal~~~~~,how can it be rendered or demodulated?
the original question:
why the quadrature mixer structure is used especially in some low if receiver, just for the convience of adding a polyphase filter to reject image?
got it! thanks to 2,3,4