jayleung
Member level 5
Hi All,
I have a question about the SSB (single-side band) modulation signal, and its circuit implementation in Radio.
For example, the baseband DAC has two I/Q differential signal outputs, and then they are connected to the corresponding differential amplifiers, and to the I/Q mixer (modulator). Then is the RF port of the mixer/modulator output single-side band signal for the regular BPSK/QPSK baseband signals? In circuit, how can it suppress the LO?
Or actually, in the baseband digital signal processing, some algorithms are used to process the BPSK/QPSK data, in order to generate the base-band SSB signal?
In my question here, the SSB is for the direct-conversion transmitter, but not the superheterodyne transmitter, which up-converts the IF to RF with SSB/Image-rejections.
Besides, in order to test the SSB image rejection level, can I just let the baseband DAC output a low frequency single-tone CW (@ Fbb), and then to use the spectrum analyzer to measure the modulator/mixer RF port, and then to compare the two tones (Flo+Fbb, Flo-Fbb) on two sides of the LO (Flo)?
Thanks in advanced.
I have a question about the SSB (single-side band) modulation signal, and its circuit implementation in Radio.
For example, the baseband DAC has two I/Q differential signal outputs, and then they are connected to the corresponding differential amplifiers, and to the I/Q mixer (modulator). Then is the RF port of the mixer/modulator output single-side band signal for the regular BPSK/QPSK baseband signals? In circuit, how can it suppress the LO?
Or actually, in the baseband digital signal processing, some algorithms are used to process the BPSK/QPSK data, in order to generate the base-band SSB signal?
In my question here, the SSB is for the direct-conversion transmitter, but not the superheterodyne transmitter, which up-converts the IF to RF with SSB/Image-rejections.
Besides, in order to test the SSB image rejection level, can I just let the baseband DAC output a low frequency single-tone CW (@ Fbb), and then to use the spectrum analyzer to measure the modulator/mixer RF port, and then to compare the two tones (Flo+Fbb, Flo-Fbb) on two sides of the LO (Flo)?
Thanks in advanced.
