| 摘要 |
<p>A method for cancelling a beat frequency in a radio receiver capable of receiving a radio signal, forming a first demodulated signal (8) by mixing a signal derived from the radio signal with a first local oscillator signal (6), and forming a second demodulated signal (9) by mixing a signal derived from the radio signal with a second local oscillator signal (7) having a quadrature relationship with the first local oscillator signal, the method comprising repeatedly performing the steps of:
a. determining the modulus of the first demodulated signal;
b. determining the modulus of the second demodulated signal;
c. comparing the modulus of the first demodulated signal with the modulus of the second demodulated signal;
d. determining a quotient by dividing the greater of the moduli of the first demodulated signal and the second demodulated signal by the lesser of the moduli of the first demodulated signal and the second demodulated signal;
e. determining a cancellation factor having the value of the reciprocal of the cosine of the arctangent of the quotient; and
f. forming a beat cancelled signal by multiplying one of the first and second demodulated signals by the cancellation factor.</p> |
