Patent ID: 6567654
Filing Date: 2003-05-20
Classification: H03D,H03J,H04B

Abstract:
A method for use with a double conversion tuner that generates a first intermediate frequency (IF) signal in response to an input signal and a first local oscillator (LO) signal, generates a second IF signal in response to the first IF signal and a second LO signal, and generates the first and second LO signals in response to a crystal reference frequency, the method for eliminating spurious signals in an IF output bandwidth of the tuner, said method comprising the steps of:selecting a crystal reference frequency that generates spurious signals only outside of the IF output bandwidth; and, (i) using two or more frequency values to determine a frequency of the first IF signal; (ii) identifying spurious signals produced by the first IF signal at the determined frequency; and (iii) if no spurious signals produced by the first IF signal at the determined frequency are in the IF output bandwidth, setting the first IF signal to the determined frequency; otherwise (iv) repeating steps (i)-(iii).