Back to results
US 6,785,348 B2Granted
Demodulator and method for demodulating CPFSK-modulated signals using a linear approximation of the CPFSK signal
AssigneeInfineon Technologies AG
InventorsMarkus Hammes, Michael Madden, Andre Neubauer, Michael Speth
Life of this patent
Estimating the term…
Abstract
In a method for demodulating a CPFSK-modulated signal, the n−1-th substitute symbol an−1 which occurs in the linear approximation of the CPFSK is estimated in order to determine an n-th input data symbol dn on which the CPFSK modulation is based. The n−1-th substitute symbol an−1 is in this case estimated on the basis of the previously determined n−1-th input data symbol {circumflex over (d)}n−1.
Claims10
A method for demodulating a CPFSK-modulated signal, which comprises:
- obtaining an estimate ân−2 of an n−1-th substitute symbol an−1, which occurs in a linear approximation of the CPFSK modulated signal, as a function of a previously determined n−1-th input data symbol {circumflex over (d)}n−1;
- and
- determining an n-th input data symbol {circumflex over (d)}n on which the CPFSK modulated signal is based by using the estimate ân−1 of the n−1-th substitute symbol an−1 occurring in the linear approximation of the CPFSK modulated signal to compare a phase angle of a currently obtained n-th complex-value sample symbol yn relative to a phase angle of the estimate ân−1 of the n−1-th substitute symbol an−1 that has been estimated for an n−1-th time step.
A devise for demodulating a CPFSK-modulated signal, comprising:
- an input data symbol decision device for determining an n-th input data symbol {circumflex over (d)}n on which the CPFSK-modulated signal is based;
- and
- a substitute symbol estimation device for estimating an n−1-th substitute symbol ân−1 occurring in a linear approximation of the CPFSK-modulated signal as a function of a previously determined n−1-th input data symbol {circumflex over (d)}n−1 said substitute symbol estimation device being constructed for estimating the n−1-th substitute symbol ân−1 using an equation:
- ân−1=ân−2 exp{jπη{circumflex over (d)}n−1}
- where ân−2 is an estimate of an n−2-th substitute symbol and η denotes a modulation index;
- said input data symbol decision device configured for using the n−1-th substitute symbol ân−1 that has been estimated for determining the n-th input data symbol {circumflex over (d)}n.
3 more elements
Dependencies are inferred from the claim text.