Selective channel tuner and tuning method
DCFirst Claim
1. A method of selectively tuning any wanted channel from a received signal, the received signal having a channelized spectrum with a uniform channel spacing, comprising:
- (a) setting a local oscillator to a first local oscillator frequency;
(b) generating a first set of I and Q signals at the first local oscillator frequency displaced more than one channel spacing from the wanted signal center frequency;
(c) mixing the first set of I and Q signals with the received signal;
(d) selecting an upper high frequency spectrum of interest above the first local oscillator frequency;
(e) setting the local oscillator to a second local oscillator frequency that is spaced from the first local oscillator frequency by an amount greater than or equal to the channel spacing;
(f) generating a second set of I and Q signals at the second local oscillator frequency;
(g) mixing the second set of I and Q signals with the received signal;
(h) selecting a lower high frequency spectrum of interest below the second local oscillator frequency;
(i) translating the selected frequency spectrum of interest to be demodulated to within a passband that is near baseband; and
(j) spacing the lower edge of the passband that is near baseband from DC by at least about an amount greater than or equal to 20 kHz.
3 Assignments
Litigations
0 Petitions
Accused Products
Abstract
A disclosed method tunes a signal from a channelized spectrum having a predetermined channel spacing. A signal of interest having a predetermined maximum bandwidth is mixed with a local oscillator signal, which has a frequency that is an integer multiple of the channel spacing or one-half of a channel spacing displaced from an integer multiple of the channel spacing. The local oscillator signal is selected to frequency translate the signal of interest to within a near-baseband passband whose lower edge is spaced from DC by at least about the maximum bandwidth of the signal of interest. Problems associated with 1/f noise, DC offsets, and self-mixing products are avoided or substantially diminished. Other methods and systems are also disclosed.
100 Citations
20 Claims
-
1. A method of selectively tuning any wanted channel from a received signal, the received signal having a channelized spectrum with a uniform channel spacing, comprising:
-
(a) setting a local oscillator to a first local oscillator frequency; (b) generating a first set of I and Q signals at the first local oscillator frequency displaced more than one channel spacing from the wanted signal center frequency; (c) mixing the first set of I and Q signals with the received signal; (d) selecting an upper high frequency spectrum of interest above the first local oscillator frequency; (e) setting the local oscillator to a second local oscillator frequency that is spaced from the first local oscillator frequency by an amount greater than or equal to the channel spacing; (f) generating a second set of I and Q signals at the second local oscillator frequency; (g) mixing the second set of I and Q signals with the received signal; (h) selecting a lower high frequency spectrum of interest below the second local oscillator frequency; (i) translating the selected frequency spectrum of interest to be demodulated to within a passband that is near baseband; and (j) spacing the lower edge of the passband that is near baseband from DC by at least about an amount greater than or equal to 20 kHz. - View Dependent Claims (2, 3)
-
-
4. A method of selectively tuning any wanted channel from a received signal, the received signal having a channelized spectrum with a uniform channel spacing, comprising:
-
(a) setting a local oscillator to a first local oscillator frequency displaced more than one channel spacing from the wanted signal center frequency; (b) generating a first set of I and Q signals at the first local oscillator frequency; (c) mixing the first set of I and Q signals with the received signal; (d) selecting a lower high frequency spectrum of interest below the first local oscillator frequency; (e) setting the local oscillator to a second local oscillator frequency that is spaced from the first local oscillator frequency by an amount greater than or equal to the channel spacing; (f) generating a second set of I and Q signals at the second local oscillator frequency; (g) mixing the second set of I and Q signals with the received signal; (h) selecting a upper high frequency spectrum of interest above the second local oscillator frequency; (i) translating the selected frequency spectrum of interest to be demodulated to within a passband that is near baseband; and
,(j) spacing the lower edge of the passband that is near baseband from DC by at least about an amount greater than 20 kHz. - View Dependent Claims (5, 6)
-
-
7. A method of selectively tuning any wanted signal from a received signal, the received signal having a channelized spectrum with a uniform channel spacing, comprising:
-
(a) setting a local oscillator to a first local oscillator frequency displaced more than one channel spacing from the wanted signal center frequency; (b) generating a first set of I and Q signals at the first local oscillator frequency; (c) mixing the first set of I and Q signals with the received signal; (d) selecting an upper high frequency spectrum of interest above the first local oscillator frequency; (e) setting the local oscillator to a second local oscillator frequency that is spaced from the first local oscillator frequency by an amount greater than or equal to the channel spacing; (f) generating a second set of I and Q signals at the second local oscillator frequency; (g) mixing the second set of I and Q signals with the received signal; (h) selecting a lower high frequency spectrum of interest below the second local oscillator frequency; (i) translating the selected upper frequency spectrum of interest to be demodulated to within a passband that is near baseband using the first set of I and Q signals; (j) combining the outputs of I and Q mixers to reject interfering image signals appearing in the passband that is near baseband; and (k) spacing the lower edge of the passband that is near baseband from DC by at least about the bandwidth of the wanted signal. - View Dependent Claims (8, 9)
-
-
10. A method of selectively tuning any wanted signal from a received signal, the received signal having a channelized spectrum with a uniform channel spacing, comprising:
-
(a) setting a local oscillator to a first local oscillator frequency displaced more than one channel spacing from the wanted signal center frequency; (b) generating a first set of I and Q signals at the first local oscillator frequency; (c) mixing the first set of I and Q signals with the received signal; (d) selecting a lower high frequency spectrum of interest below the first local oscillator frequency; (e) setting the local oscillator to a second local oscillator frequency that is spaced from the first local oscillator frequency by an amount greater than or equal to the channel spacing; (f) generating a second set of I and Q signals at the second local oscillator frequency; (g) mixing the second set of I and Q signals with the received signal; (h) selecting a upper high frequency spectrum of interest above the second local oscillator frequency; (i) translating the selected high frequency spectrum of interest to be demodulated to within a passband that is near baseband; and (j) spacing the lower edge of the passband that is near baseband from DC by at least about the bandwidth of the wanted signal. - View Dependent Claims (11, 12)
-
-
13. A method of selecting and switching between an upper high frequency spectrum of interest and a lower high frequency spectrum of interest associated with a down-converted signal of interest being any one selected channel from among a plurality of channels from a channelized spectrum having a uniform channel spacing, comprising:
-
(a) adjusting a local oscillator to a first local oscillator frequency displaced more than one channel spacing from the wanted signal center frequency; (b) mixing the first local oscillator frequency with the channelized spectrum; (c) down-converting a radio frequency signal to a passband that is near baseband; (d) spacing the lower edge of the passband that is near baseband from DC by at least an amount greater than 20 kHz; (e) selecting and demodulating either an upper or lower high frequency spectrum of interest associated with the down-converted radio frequency signal and the first local oscillator frequency; (f) adjusting the local oscillator to a second local oscillator frequency that is spaced from the first local oscillator frequency by an amount greater than or equal to the channel spacing; (g) mixing the second local oscillator frequency with the channelized spectrum; (h) down-converting the radio frequency signal to the passband that is near baseband; (i) spacing the lower edge of the passband that is near baseband from DC by at least an amount greater than 20 kHz; (j) switching from the selected upper or lower high frequency spectrum of interest generated using the first local oscillator frequency to a selected lower or upper high frequency spectrum of interest, respectively, generated using the second local oscillator frequency.
-
-
14. A method of tuning channels of interest from a channelized spectrum comprising:
-
(a) mixing a channel of interest from a channelized spectrum having a predetermined channel spacing with a first local oscillator signal, having a first frequency that is; (1) one half of a channel spacing displaced from the center frequency of the channel of interest; and (2) selected to frequency translate the channel of interest to within a passband that is near baseband and that extends near to but excludes DC; (b) mixing the channel of interest with a second local oscillator signal having the first frequency and being approximately in quadrature with the first local oscillator signal; and (c) selecting between; (1) providing spectrum coverage within a lower high frequency spectrum of interest and not an upper high frequency spectrum of interest; and (2) providing spectrum coverage within an upper high frequency spectrum of interest and not a lower high frequency spectrum of interest; (d) wherein the channel of interest; (1) has a predetermined maximum bandwidth less than the channel spacing; and (2) lies within one of an upper high frequency spectrum of interest and a lower high frequency spectrum of interest. - View Dependent Claims (15, 16, 17, 18)
-
-
19. A method of tuning any one selected channel from among a plurality of selected channels of interest from a plurality of channels comprising:
-
(a) at a first time, mixing a first selected channel of interest with a first local oscillator signal that has a frequency displaced above the first selected channel of interest by more than a channel spacing; (b) at a second time, mixing a second selected channel of interest with a second local oscillator signal that has a frequency displaced below the second selected channel of interest by more than a channel spacing; (c) frequency translating to a passband that is near baseband either the first selected channel of interest or the second selected channel of interest; and (d) reducing an image frequency of either the first selected channel of interest or the second selected channel of interest. - View Dependent Claims (20)
-
Specification