Patent ID: 6829469
Filing Date: 2004-12-07
Classification: H03D,H04B

Abstract:
A method for producing a first output signal (42), which has a specific first output frequency, in a receiver from a first input signal (40), which has an input frequency resolution and a first input frequency belonging to an input frequency band, which changes in steps of the size of the input frequency resolution or a multiple of the input frequency resolution on the input frequency band, and which method comprises the steps of:determining said first input frequency from the input frequency band; producing a first local oscillator signal (44), which has a frequency, by a first local oscillator (43), which has a first frequency resolution, the first local oscillator signal (44) obtains frequency values from a first frequency band and which values are at a distance of the first frequency resolution or a multiple of the first frequency resolution from each other; producing a second local oscillator signal (46), which has a frequency, by a second local oscillator (45); receiving said first input signal; producing a first intermediate frequency signal (41), which has a first intermediate frequency, by converting the first input signal (40) by the first local oscillator signal (44); producing a first output signal (42) by down-converting the first intermediate frequency signal (41) by a second local oscillator signal (46), characterised in thatthe first intermediate frequency signal (41) has a first intermediate frequency resolution, which is higher than the input frequency resolution; the first intermediate frequency signal obtains frequency values from a first intermediate frequency band, which values are at a distance of the first intermediate frequency resolution or a multiple of the first intermediate frequency resolution from each other; the first frequency resolution is higher than the input frequency resolution; the second local oscillator (45) has a second frequency resolution, which is higher than the input frequency resolution, and the frequency of the second local oscillator signal (46) obtains frequency values from a second frequency band, which values are at a distance of the second frequency resolution or a multiple of the second frequency resolution from each other; and that the method further comprises the steps of:adjusting the difference or sum of the first intermediate frequency and the first input frequency as the frequency of the first local oscillator signal (44) and the difference or sum of the first intermediate frequency and the first output frequency as the frequency of the second local oscillator signal (46), so that the value of said first intermediate frequency is determined from the first intermediate frequency band on the basis of the first input frequency and the first frequency resolution.