Demodulation structure and method

Demodulation structure for downconverting and demodulating a digitally modulated signal, comprising:

• a local oscillator means for providing a local oscillator signal,
• a mixer means for mixing said local oscillator signal and said digitally modulated signal in order to obtain a mixed signal,
• a low pass filter means for low pass filtering said mixed signal from said mixer means, and
• an analog-to-digital converting means for converting the filtered signal from said low pass filter means into a downconverted and demodulated digital signal,
• whereby said local oscillator signal is set in respect to said digitally modulated signal so that said downconverted and demodulated digital signal output from said analog-to-digital convening means comprises two serially arranged information parts whereby said local oscillator signal is modulated with at least two modulation states having different phases during the symbol period of the digitally modulated signal,
• a modulation control means for supplying a modulation signal to said local oscillator means in order to internally modulate the local oscillator signal with said at least two modulation states;
• and
• a band pass filter for band pass filtering said modulated local oscillator signal.

Method for downconverting and demodulating a digitally modulated signal, comprising the steps of:

• providing a local oscillator signal,
• mixing said local oscillator signal and said digitally modulated signal in order to obtain a mixed signal,
• low pass filtering said mixed signal, and
• analog-to-digital converting the filtered signal into a downconverted and demodulated digital signal,
• whereby said local oscillator signal is set in respect to said digitally modulated signal so that said downconverted and demodulated digital signal comprises two serially arranged information parts, and
• wherein that said digitally modulated signal is modulated in a signal band having a center frequency and said local oscillator signal has a center frequency, which is, in respect to said center frequency of the signal band, offset by half of the signal band width of the digitally modulated signal.

Method for downconverting and demodulating a digitally modulated signal, comprising the steps of:

• providing a local oscillator signal,
• mixing said local oscillator signal and said digitally modulated signal in order to obtain a mixed signal,
• low pass filtering said mixed signal,
• analog-to-digital converting the filtered signal into a downconverted and demodulated digital signal,
• whereby said local oscillator signal is set in respect to said digitally modulated signal so that said downconverted and demodulated digital signal comprises two serially arranged information parts,
• whereby said local oscillator signal is modulated with at least two modulation states having different phases during the symbol period of the digitally modulated signal,
• whereby the local oscillator signal is internally modulated with said at least two modulation states by means of a supplied modulation signal, and
• whereby said two different modulation states have the same magnitude and a 90 degree phase shift in respect to each other, and further comprising the step of
• band pass filtering said modulated local oscillator signal.