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Title:
SYSTEMS AND METHOD FOR REDUCING SPURIOUS SIGNALS IN A RECEIVED SIGNAL
Document Type and Number:
WIPO Patent Application WO/2020/058980
Kind Code:
A4
Abstract:
A receiving system for reducing spurious signals in a received signal which includes a first receive, at least a second receiver coupled with processor. The first receiver employs a first mixing-scheme and down-converts a received-signal to a first selected Nyquist-zone, and produces a first down-converted received-signal. The first receiver further samples the first down-converted received-signal and produces a first sampled-signal. The second receiver employs a second mixing-scheme, down-converts the received-signal to a second selected Nyquist-zone, different from the first selected Nyquist-zone, produces a second down-converted received-signal, samples the second down-converted received-signal and produces a second sampled-signal. The processor produces a first frequency-domain-representation of the first sampled-signal and at least a second frequency-domain-representation of the second sampled-signal. The processor further produces a modified frequency-domain-representation from a combination of at least portions the first frequency-domain-representation and at least portions of at least the second frequency-domain-representation.

Inventors:
PILAS MARCO
BEN TSUR ELIYAHU EYAL
GOLDREICH RAM YERACHMIEL
LERER NACHUM
Application Number:
PCT/IL2019/051042
Publication Date:
May 14, 2020
Filing Date:
September 19, 2019
Export Citation:
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Assignee:
ELBIT SYSTEM BMD AND LAND EW ELISRA LTD (IL)
International Classes:
H04B1/10; H04B1/26
Attorney, Agent or Firm:
KORAKH, Eliav et al. (IL)
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Claims:
AMENDED CLAIMS

received by the International Bureau on 19 March 2020 (19.03.2020)

[Claim 1] A receiving system for reducing spurious signals in a received signal

comprising:

a first receiver, employing a first mixing scheme, said first receiver down-converting a received signal to a first selected Nyquist zone, and for producing a first down-converted received signal, said first receiver further being for sampling said first down-converted received signal and for producing a first sampled signal;

at least a second receiver, employing a second mixing scheme, said second receiver being for down-converting said received signal to a second selected Nyquist zone, different from said first selected Nyquist zone, and for producing a second down-converted received signal, said second receiver further being for sampling said second down-converted received signal and for producing a second sampled signal;

a processor, coupled with said first receiver and with said second

receiver, said processor being for producing a first frequency domain representation from said first sampled signal and a second frequency domain representation from said second sampled signal, said processor further being for producing a modified frequency domain repre

sentation from a combination of at least portions of said first frequency domain representation and at least portions of at least said second

frequency domain representation, by comparing said first frequency domain representation with said second frequency domain repre

sentation,

said processor determines a value of a frequency in said modified

frequency domain representation from at least one of values of the cor responding frequency in said first frequency domain representation and said second frequency domain representation, when the values of said frequency in said first frequency domain representation and in said second frequency domain representation are similar, and

said processor selects a value of the corresponding frequency in said modified frequency domain representation from a frequency domain representation corresponding to one of said first receiver and said

second receiver which is known to not exhibit interferences in that frequency, when said values of a frequency in said first frequency

domain representation and in said second frequency domain repre sentation are different. [Claim 2] The system according to claim 1 , wherein frequencies which do not exhibit interferences are determined by spectral pre-mapping identify the frequencies in which interference occurs in each of said first receiver and said second receiver.

[Claim 3] The system according to claim 2, wherein when said receiving system is employed in a communication systems that do not continuously transmit, time periods in which said first receiver and at least said second receiver do not receive a signal are employed for said spectral pre-mapping,

wherein in said time periods, any value corresponding to a frequency in either said first frequency domain representation or said second frequency domain representation, which is greater than an expected noise, is determined as a spurious signal.

[Claim 4] The system according to claim 2, when said receiving system is

employed in synchronized communication systems, a synchronizing signal is employed for spectral pre-mapping,

wherein an expected received spectrum of a synchronizing signal is de termined,

wherein each of the first frequency domain representation and the second frequency domain representation is compared with said expected received spectrum,

wherein when a value of a frequency in one of the frequency domain representation is different from the expected received spectrum, than that frequency is determined as including a spurious signal.

[Claim 5] The system according to claim 1, wherein each of said first mixing scheme and said second mixing scheme is one of zero-IF, low-IF and super-heterodyne.

[Claim 6] The system according to claim 5, wherein said first mixing scheme is zero-IF and said second mixing scheme is low-IF.

[Claim 7] The system according to claim 1 , wherein said first mixing scheme is zero-IF and said second mixing scheme is super-heterodyne.

[Claim 8] The system according to claim 1, wherein said processor further

produces a time domain signal from said modified frequency domain representation.

[Claim 9] A method for reducing spurious signals in a received signal comprising the procedures of:

down-converting a received signal to a first selected Nyquist zone employing a first mixing scheme, thereby producing a first down- 38

converted signal;

down-converting said received signal to at least a second selected Nyquist zone, different from said first selected Nyquist zone, employing at least a second mixing scheme, thereby producing at least a second down-converted signal;

sampling said first down-converted signal, thereby producing a first sampled signal;

sampling at least said second down-converted signal, thereby producing at least a second sampled signal;

producing a first frequency domain representation from said first sample signal;

producing at least a second frequency domain representation from said second sample signal; and

producing a modified frequency domain representation from a com bination of at least portions said first frequency domain representation and at least portions of said second frequency domain representation, by comparing said first frequency domain representation with said second frequency domain representation,

wherein when values of a frequency in said first frequency domain rep resentation and in said second frequency domain representation are similar, than a value of the corresponding frequency in said modified frequency domain representation is determined from at least one of the said values, and

wherein when said values of a frequency in said first frequency domain representation and in said second frequency domain representation are different, then, said processor selects a value of the corresponding frequency in said modified frequency domain representation from a frequency domain representation corresponding to one of said first down-converted signal and said second down-converted signal which is known to not exhibit interferences in that frequency.

[Claim 10] The method according to claim 9, wherein frequencies which do not exhibit interferences are determined by spectral pre-mapping identify the frequencies in which interference occurs.

[Claim 11] The method according to claim 10, wherein in communication systems that do not continuously transmit, time periods in which a signal is not received are employed for said spectral pre-mapping,

wherein in said time periods, any value corresponding to a frequency in either said first frequency domain representation or said second 39 frequency domain representation, which is greater than an expected noise, is determined as a spurious signal.

[Claim 12] The method according to claim 10, wherein in synchronized commu nication systems, a synchronizing signal is employed for spectral pre mapping,

wherein an expected received spectrum of a synchronizing signal is de termined,

wherein each of the first frequency domain representation and the second frequency domain representation is compared with said expected received spectrum,

wherein when the value of a frequency in one of the frequency domain representation is different from the expected received spectrum, than that frequency is determined as including a spurious signal.

[Claim 13] The method according to claim 9, further including the procedure of producing a time domain signal from said modified frequency domain representation.

[Claim 14] The system according to claim 9, wherein each of said first mixing scheme and said second mixing scheme is one of zero-IF, low-IF and super-heterodyne.

[Claim 15] The system according to claim 14, wherein said first mixing scheme is zero-IF and said second mixing scheme is low-IF.

[Claim 16] The system according to claim 9, wherein said first mixing scheme is zero-IF and said second mixing scheme is super-heterodyne.