Method for detecting and attenuating interference effects in a signal of a radio receiver having multiple tuners

Abstract

A method for detecting and attenuating interference effects in a signal of a radio receiver (10) having a plurality of tuners, the method comprising the steps of: providing a first tuner T 1 Provide a first input signal RF 1 ; At the same time to the second tuner T 2 Provide a second input signal RF 2 ; Perform the following two actions simultaneously: With the help of the first tuner T 1 Based on the first frequency f E The first input signal RF is filtered 1 Generates the first high injection intermediate signal IFH 1 , and with the aid of the second tuner T 2 Based on the first frequency f E The second input signal RF is filtered 2 Generates a first low injection intermediate signal IFB 2 ; Compare the first high injection intermediate signal IFH 1 and the first low injected intermediate signal IFB 2 ; Select the first high injection intermediate signal IFH 1 and the first low injected intermediate signal IFB 2 for decoding by a radio receiver (10).

Description

Technical Field

[0001] The present disclosure relates to a method for detecting and attenuating interference effects in a signal of a radio receiver having multiple tuners. The present disclosure also relates to a radio receiver having multiple tuners for implementing such a method. Background Art

[0002] A radio receiver for a vehicle, in particular a motor vehicle, generally comprises one or more antennas which capture signals in the form of radio communication electromagnetic waves, each of which is characterized by a certain frequency range, and convert them into electrical signals. The radio receiver may also comprise a plurality of tuners, each of which makes it possible to select a signal according to a desired channel from the signals received by at least one antenna.

[0003] In general, the tuner of a radio receiver comprises a plurality of filters and at least one mixer to enable the received radio signal to be combined with the signal of a local oscillator. The intermediate signal from the tuner is then demodulated and amplified in the form of an audio signal.

[0004] Current radio receivers with multiple tuners typically include a large number of mixers, local oscillators, and filters to process multiple signals simultaneously, improve audio listening quality, facilitate changes, or provide information to the vehicle's user. However, all of these components can generate interference that affects the intermediate signals produced by the tuners.

[0005] The current solution is to divide these components into modules that are electrically and magnetically isolated from each other and connect them together with coaxial cables. However, the disadvantage of such a setup is that it takes up a lot of space and is not economical.

[0006] Furthermore, for the purpose of attenuating interfering signals, radio receivers with multiple tuners typically include complex mixing algorithms and filters. However, such filters and algorithms are limited in their effectiveness in attenuating interference in signals and have the disadvantage of being expensive.

[0007] In addition, current motor vehicles include more and more electronic devices, which may generate parasitic electromagnetic waves compatible with the selected frequency range. These parasitic electromagnetic waves generate interference, which may affect the collection of radio signals by at least one of the one or more antennas of the vehicle.

[0008] Therefore, there is a need for improved detection and attenuation of interference in signals of radio receivers. Summary of the invention

[0009] The present disclosure improves this situation.

[0010] A method for detecting and attenuating interference effects in a signal of a radio receiver having multiple tuners is proposed, the method comprising the following steps:

[0011] a. providing a first input signal to a first tuner,

[0012] b. simultaneously with step a, providing a second input signal to a second tuner,

[0013] c. simultaneously performing the following two actions: generating a first high injection intermediate signal based on a first input signal filtered at a first frequency by means of a first tuner, and generating a first low injection intermediate signal based on a second input signal filtered at a first frequency by means of a second tuner,

[0014] d. comparing the first high injection intermediate signal and the first low injection intermediate signal,

[0015] e. Selecting the better quality one of the first high injection intermediate signal and the first low injection intermediate signal for decoding by the radio receiver.

[0016] Such a method thus enables the selection of an intermediate signal of better quality, thereby ultimately reducing the impact of interference on the audio signal emitted by the radio receiver.

[0017] In particular, such a method enables detection and limitation of the influence of internal electromagnetic emissions constituting interference in at least one of the intermediate signals from the tuner.

[0018] Furthermore, such an approach has the advantage of reducing the size and complexity of the radio receiver.

[0019] The term "high injection intermediate signal" refers to a signal generated by a mixer based on an input signal and a local oscillator signal whose frequency is higher than the frequency of the input signal, in particular by multiplying these two signals. Here, a first high injection intermediate signal is generated by mixing a first input signal with a local oscillator signal whose frequency is higher than a first frequency of the first input signal.

[0020] The term "low injection intermediate signal" refers to a signal generated by a mixer based on an input signal and a local oscillator signal whose frequency is lower than the frequency of the input signal, in particular by multiplying these two signals. Here, the first low injection intermediate signal is generated by mixing the second input signal with a local oscillator signal whose frequency is lower than the first frequency of the second input signal.

[0021] According to a first example, the first input signal and the second input signal are acquired by means of a single antenna.

[0022] According to a second example, the first input signal is acquired by means of a first antenna and the second input signal is acquired by means of a second antenna, the method comprises steps f and g, which consist in:

[0023] f. performing the following two actions simultaneously: generating a second low injection intermediate signal based on the first input signal filtered at the first frequency by means of the first tuner, and generating a second high injection intermediate signal based on the second input signal filtered at the first frequency by means of the second tuner,

[0024] g. comparing the second lowest injected intermediate signal to the second highest injected intermediate signal,

[0025] Steps f and g are performed between steps d and e, step e consisting in selecting the best quality one of the first high injection intermediate signal, the first low injection intermediate signal, the second low injection intermediate signal and the second high injection intermediate signal for decoding by the radio receiver.

[0026] According to an advantageous arrangement of the second example of the method, it is possible to detect when an external electromagnetic emission affects at least one antenna so as to generate interference in one of the input signals around a first frequency. Thus, the influence of the interference caused by the external electromagnetic emission can be limited by selecting the intermediate signal with the best quality for decoding by the radio receiver.

[0027] Here, the second low injection intermediate signal is generated by mixing the first input signal with a local oscillator signal having a frequency lower than the first frequency of the first input signal. The second high injection intermediate signal is generated by mixing the second input signal with a local oscillator signal having a frequency higher than the first frequency of the second input signal.

[0028] According to the first aspect of the second example of the method, step c is performed at a first moment and step f is performed at a second moment, the first moment and the second moment are separated by a certain time interval, the first input signal and the second input signal remain unchanged during the time interval, and the time interval is preferably equal to 10ms.

[0029] Such a time interval enables real-time detection of interference affecting at least one intermediate signal of the radio receiver. This also enables continuity of the audio stream output by the radio receiver to be ensured while the method is being implemented. The user of the radio receiver can then enjoy uninterrupted continuous listening.

[0030] According to an advantageous aspect of the above method in all its combinations, step c comprises a supplementary step consisting in digitizing the first high injection intermediate signal and the first low injection intermediate signal.

[0031] According to an advantageous aspect of the second example of the above method, step f comprises an auxiliary step consisting in digitizing the second low injection intermediate signal and the second high injection intermediate signal.

[0032] Digitally converting the intermediate signals from the first and second tuners enables the intermediate signals to be stored. Furthermore, digitally converting the intermediate signals enables the reduction or even prevention of parasitage due to interference when processing the intermediate signals during steps c to e in both the first and second examples.

[0033] According to one aspect of the above method in all its combinations, step d comprises the following sub-steps:

[0034] i. determining a first difference signal between the power spectral density of the first high injected intermediate signal and the power spectral density of the first low injected intermediate signal,

[0035] ii. Analyzing the first difference signal.

[0036] According to one aspect of the second example of the above method, step g also includes the following sub-steps:

[0037] i. determining a second difference signal between the power spectral density of the second low injected intermediate signal and the power spectral density of the second high injected intermediate signal,

[0038] ii. Analyzing the second difference signal.

[0039] According to an advantageous aspect of the above method, sub-step ii comprises evaluating the first difference signal relative to an interference threshold. Similarly, in the case of the second example of the method, sub-step ii comprises evaluating the second difference signal relative to an interference threshold.

[0040] Evaluating the difference signal relative to an interference threshold enables elimination of differences between the intermediate signal from the first tuner and the intermediate signal from the second tuner, which differences are caused by residual noise inherent to components of the radio receiver.

[0041] According to an advantageous aspect of the above method, sub-step ii comprises evaluating the sign of the first difference signal. Similarly, in the case of the second example of the method, sub-step ii comprises evaluating the sign of the second difference signal.

[0042] This enables identification of which tuner receives the internal electromagnetic transmission, and / or possibly which antenna receives the external electromagnetic transmission.

[0043] According to a further aspect, a radio receiver for a motor vehicle is proposed for carrying out the method as described above in all its combinations, the radio receiver having a plurality of tuners, the radio receiver comprising at least a first antenna and a second antenna and a central digital part for signal processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other features, details and advantages will become apparent from a reading of the following detailed description and an analysis of the accompanying drawings, in which:

[0045] Figure 1 The vehicle's radio receiver is schematically shown.

[0046] Figure 2 Schematically and in more detail Figure 1 A radio receiver,

[0047] Figure 3 shows the purpose of detecting and attenuating Figure 1 and Figure 2 Flowchart of a first example of a method of decoding interference in a signal by a radio receiver,

[0048] Figure 4 Schematically shows that in the first case Figure 3 A first example of the method,

[0049] Figure 5 Schematically shows that in the second case Figure 3 A first example of the method,

[0050] Figure 6 shows the purpose of detecting and attenuating Figure 1 and Figure 2 Flowchart of a second example of a method of decoding interference in a signal by a radio receiver,

[0051] Figure 7 Schematically shows that in the first case Figure 6 A second example of the method,

[0052] Figure 8 Schematically shows that in the second case Figure 6 A second example of the method,

[0053] Figure 9a shows the operation of the mixer in the case of high injection,

[0054] Figure 9b The operation of the mixer in the case of low injection is shown. DETAILED DESCRIPTION

[0055] The following drawings and descriptions contain elements with specific features out of necessity. Therefore, they can be used not only to help better understand the present disclosure, but also to help define the present disclosure when necessary.

[0056] In the various figures, the same reference numerals denote the same or similar elements. For the sake of brevity, only those elements useful for understanding the described embodiments are shown in the drawings and are described in detail below. Only the differences between the presented examples are described in detail.

[0057] Figure 1 A radio receiver 10 of a vehicle, in particular a motor vehicle, is schematically shown. The radio receiver 10 has a plurality of tuners, ie it comprises at least two tuners. Figure 1 In the example of the present invention, the radio receiver 10 includes a first tuner T1 connected to a first antenna A1. Similarly, the radio receiver 10 includes a second tuner T2 connected to a second antenna A2. According to another example described below, the first tuner T1 and the second tuner T2 can be connected to the same antenna. Optionally, the third tuner T3 and the fourth tuner T4 can be connected to the third antenna A3 and the fourth antenna A4, respectively.

[0058] The following is a description of the tuner T, which applies to each tuner T1, T2 of the radio receiver 10 in this specification. The tuner T is connected to an antenna A. The tuner T receives an input signal RF received by the antenna A. The input signal RF includes a large number of frequencies, each frequency carrying information to be decoded. First, the tuner T enables the selected input frequency f to be decoded. E Filter the input signal RF, the input frequency f of the input signal RF E In particular, it carries the information to be decoded. In the following part of this specification, the “input frequency f E " refers to the frequency at which the user of the radio receiver 10 wishes to decode the input frequency f of the input signal E The frequency of the information carried. Input frequency f E It may in particular be between 88 MHz and 108 MHz, for example.

[0059] The tuner T also includes a mixer. The mixer combines the filtered input signal RF with a local oscillator signal LO to generate an intermediate signal IF having an intermediate frequency f IF Relative to the input frequency f E In particular, the intermediate frequency f of the intermediate signal IF IF The input frequency f is equal to the input signal RF E and the frequency f of the local oscillator signal LO LO The absolute value of the difference.

[0060] In addition, the frequency f of the mixer's local oscillator signal LO LO is variable. Therefore, the frequency f of the local oscillator signal LO LO can be controlled so that the desired intermediate frequency f of the intermediate signal IF is obtained IF In addition, there are two different frequencies f LO This enables the same desired intermediate frequency f of the intermediate signal IF to be obtained IF .

[0061] according to Figure 9a In the first case shown, the frequency f of the local oscillator signal LO LO The input frequency f is higher than the input signal RF E In this first case, the intermediate signal IF obtained is called high injection intermediate signal IFH. The intermediate frequency f of the high injection intermediate signal IFH IFH Equal to the frequency f of the local oscillator signal LO LO and the input frequency f of the input signal RF E difference.

[0062] according to Figure 9b In the second case shown, the frequency f of the local oscillator signal LO LO The input frequency f is lower than the input signal RF E In this second case, the intermediate signal IF obtained is called low injection intermediate signal IFB. The intermediate frequency f of the intermediate signal IF IFB The input frequency f is equal to the input signal RF E and the frequency f of the local oscillator signal LO LO difference.

[0063] In the following, unless explicitly stated otherwise, the "intermediate signal IF" will indiscriminately refer to the high injection or the low injection intermediate signal.

[0064] Furthermore, unless otherwise stated, the tuners T1, T2 are parameterized here so as to generate first and second intermediate signals IF1 and IF2, respectively, each having an intermediate frequency f close to or even identical to each other. IF In addition, the intermediate frequency f of each intermediate signal IF1, IF2 IF A standard value, for example 10.7 MHz, may be set. This arrangement makes it possible, in particular, to facilitate the processing and / or comparison of the intermediate signals IF1 , IF2 .

[0065] refer to Figure 1, the radio receiver 10 also includes a central digital part 12 with a logic control unit (digital core), and a downstream analog part with an amplifier and a speaker 16. An analog-to-digital converter 14 separates the central digital part from the tuners T1, T2. Similarly, a digital-to-analog converter 15 separates the central digital part 12 from the downstream analog part. In addition, the audio system includes a user interface with a display screen 18 ("display") and a touch-sensitive surface and / or physical buttons (not shown) that enable the user to select an input frequency f E .

[0066] Figure 2 A central digital part 12 of a radio receiver 10 is shown schematically and in more detail for implementing the interference detection and attenuation method discussed in more detail below.

[0067] like Figure 2 As shown, the central digital part 12 comprises in particular a first block 19 for moving the first and second intermediate signals IF1, IF2 from the first and second tuners T1, T2, respectively, to baseband. Each intermediate signal IF1, IF2 in baseband can then be stored in a data buffer of the first block 19. A Fourier transform analysis is performed based on the stored data, which gives as output of the first block 19 a power spectral density curve representing the first intermediate signal IF1 and a power spectral density curve representing the second intermediate signal IF2.

[0068] The central digital part 12 comprises at least a first comparator block C1. The central digital part 12 may also comprise a second comparator block C2. Each comparator block C1, C2 determines a first difference signal and a second difference signal, respectively. Each difference signal corresponds to the difference between a power spectral density curve representing the first intermediate signal IF1 and a power spectral density curve representing the second intermediate signal IF2.

[0069] The central digital part 12 comprises a selection block S which enables the difference signals calculated by the comparator blocks C1, C2 to be subsequently analyzed. In particular, the selection block S enables each difference signal to be evaluated relative to a predefined threshold value. The selection block S also enables the sign of each difference signal to be evaluated. Depending on the result of the analysis of the difference signal between the intermediate signal IF1 and the intermediate signal IF2, the selection block S is then able to select one of the intermediate signal IF1 and the intermediate signal IF2 for demodulation by the demodulation block D. It is known that a demodulated audio signal is obtained by such a demodulation block D. Therefore, the demodulation block D will not be described in more detail here.

[0070] Some or all of the operations of shifting, storing, Fourier transforming, comparing, analyzing, selecting, and demodulating may be performed by dedicated circuits of the DSP (digital signal processor) type.

[0071] Figure 3 A flow chart showing a first example of a method for detecting and attenuating interference in a signal intended to be decoded by a radio receiver 10 as described above is shown. Figure 4 A first example of the method in the first case is described in more detail.

[0072] The first step 110 of the first example of the method consists in collecting radio communication electromagnetic waves by means of an antenna A1. The first input signal RF1 is then transmitted to the first tuner T1. Similarly, the second input signal RF2 is transmitted to the second tuner T2. For this purpose, the first tuner T1 and the second tuner T2 are each connected to the antenna A1. Therefore, the first signal RF1 is identical to the second signal RF2. Here and in the following, "identical" means that the first signal RF1 and the second signal RF2 have the same spectrum and differ only in the residual noise inherent to the components of the radio receiver 10.

[0073] In a second step 120, each input signal RF1, RF2 is firstly tuned by the tuner T1, T2 at the same input frequency f E Filtering. The tuner T1 then generates a first high injection intermediate signal IFH1 based on the filtered first input signal RF1. At the same time, the tuner T2 generates a first low injection intermediate signal IFB2 based on the filtered second input signal RF2. Here, the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 have the same intermediate frequency f IF It should also be noted that the input frequency f of the first input signal RF1 E The input frequency f carrying the second input signal RF2 E Therefore, the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 also carry the same information derived from the input signals RF1 and RF2, respectively.

[0074] like Figure 4 As shown, the tuner T1 receives the internal electromagnetic emission 20. The internal electromagnetic emission 20 is emitted by a component inside the radio receiver 10. The internal electromagnetic emission 20 may be, for example, a harmonic from a mixer of the second tuner T2. The internal electromagnetic emission 20 disturbs the first tuner T1 to generate a first high injection intermediate signal IFH1. For example, the internal electromagnetic emission 20 has a frequency f close to the first high injection intermediate signal IFH1. IF Thus, the interference is superimposed on the first high injection intermediate signal IFH1. Or the internal electromagnetic emission 20 has a frequency f close to the local oscillator signal LO of the first tuner T1. LOThe input signal RF1 is then combined with the local oscillator signal LO including the interference to generate a first high injection intermediate signal IFH1 also including the interference. The interference may parasitically disturb the information carried by the first high injection intermediate signal IFH1.

[0075] In contrast, here, the first low injection intermediate signal IFB2 does not have any interference. Therefore, the information carried by the first low injection intermediate signal IFB2 will not be corrupted.

[0076] Then in a third step 130 , the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 are converted into digital signals.

[0077] The fourth step 140 is performed by the first block 19 of the central digital part 12 and then consists in shifting the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 to baseband. A first power spectral density curve 22 representing the first high injection intermediate signal IFH1 and a second power spectral density curve 24 representing the first low injection intermediate signal IFB2 are then formed.

[0078] The first curve 22 differs from the second curve 24 in that the interference causes a power excess 26 in a portion of the frequency spectrum associated with the first high injection intermediate signal IFH1. Obviously, the first curve 22 representing the first high injection intermediate signal IFH1 can have multiple power excesses 26, each power excess being related to the interference superimposed on the first high injection intermediate signal IFH1. Apart from this, the first curve 22 and the second curve 24 are identical in the frequency range not disturbed by the interference. It should be noted that in the absence of interference, the first curve 22 and the second curve 24 are identical in the entire frequency domain. Here, again, "identical" means that the difference between the first curve 22 and the second curve 24 is only the residual noise affecting the first high injection intermediate signal IFH1 and / or the first low injection intermediate signal IFB2.

[0079] Then, in a fifth step 150, the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 are compared by means of the first comparator block C1. In particular, the first comparator block C1 determines the first difference signal 28. The first difference signal 28 originates from the difference between the first curve 22 and the second curve 24.

[0080] Therefore, the first difference signal 28 obtained by the first comparator block C1 then shows a signal close to or even equal to zero in the frequency range in which the first high injection intermediate signal IFH1 is not disturbed by the interference. In addition, the first difference signal 28 includes a power peak 30 corresponding to the power excess 26 associated with the interference that disturbs the first high injection intermediate signal IFH1. Here, the power peak 30 is positive. As described below, in other cases, the power peak 30 can also be negative.

[0081] In a sixth step 160, the selection block S determines the presence of a power peak 30 by comparing the difference signal 28 with a predefined threshold. The threshold makes it possible in particular to distinguish the power peak 30 from a frequency range of the first difference signal 28 close to zero but not zero, which originates from residual noise affecting the first high injection intermediate signal IFH1 and / or the first low injection intermediate signal IFB2.

[0082] In a sixth step 160, the selection block S also evaluates the sign of the power peak 30. In fact, the interference is superimposed on the first high injection intermediate signal IFH1. The interference causes a power excess 26 on the first power spectral density curve 22 of the first high injection intermediate signal IFH1 only at the transmission frequency of the interference. Thus, the interference superimposed on the first high injection intermediate signal IFH1 here only causes a positive power peak 30 on the first difference signal 28. Similarly, and as described below, the interference superimposed on the first low injection intermediate signal IFB2, on the contrary, only causes a negative power peak 30 on the first difference signal 28. However, this depends on the order in which the difference between the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 is determined.

[0083] Therefore, the evaluation of the sign of the power peak 30 enables the selection block S to determine which of the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 is affected by the interference. Figure 4 In this case, the selection block S determines that the first high injection intermediate signal IFH1 is affected by interference.

[0084] With the aid of this information, the selection block S advantageously decodes the one of the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 that has less interference. Thus, the audio signal from the selected intermediate signal is not parasitically disturbed by interference. Figure 4 In this case, the selection block S selects the first low injection intermediate signal IFB2 for decoding. However, the first high injection intermediate signal IFH1 can be used for lower priority functions, such as alternative frequency quality testing.

[0085] Therefore, in a seventh step 170 , the demodulation block D demodulates the first low injection intermediate signal IFB2 . In an eighth step 180 , the demodulated signal is converted into an analog signal in order to be sent to the amplifier and the loudspeaker 16 .

[0086] Figure 5 A first example of the method in the second case is shown. The second case differs from the first case mainly in that it is the second tuner T2 that receives the internal electromagnetic emission 20. The interference is then superimposed on the first low injection intermediate signal IFB2 obtained in the second step 120.

[0087] The second power spectral density curve 24 representing the first low injection intermediate signal IFB2 determined in the fourth step 140 then shows a power excess 26 in a portion of the spectrum associated with the first low injection intermediate signal IFB2. Here, the first curve 22 is free of any disturbances.

[0088] The first difference signal 28 obtained in the fifth step 150 then has a negative power peak 30 . In a sixth step 160 , the selection block S determines that the first low injection intermediate signal IFB2 is affected by interference and therefore selects the first high injection intermediate signal IFH1 for decoding in a seventh step 170 .

[0089] Figures 6 to 8 It concerns a second example of a method for detecting and attenuating interference affecting a signal intended to be decoded by a radio receiver 10 as described above. Figure 6 A flow chart of a second example of the method is shown. First, the following reference Figure 7 Let's describe the first case of the second example of this method.

[0090] like Figure 7 As shown, the first tuner T1 is connected to the first antenna A1. Similarly, the second tuner T2 is connected to the second antenna A2.

[0091] The second example of the method comprises a first step B (bis) 110'. The first step B 110' consists in simultaneously acquiring a first input signal RF1 by means of a first antenna A1 and a second input signal RF2 by means of a second antenna A2. The first input signal RF1 is transmitted to a first tuner T1. Similarly, the second input signal RF2 is transmitted to a second tuner T2. The first input signal RF1 and the second input signal RF2 are acquired simultaneously, so each carries the same information.

[0092] exist Figure 7 In the first case shown, the second antenna A2 receives external electromagnetic radiation 31 emitted by other components of the vehicle. Here, the external electromagnetic radiation 31 has a frequency close to the input frequency f E The acquisition of the second input signal RF2 by the second antenna A2 is thus disturbed. The interference is superimposed on the second input signal RF2, especially at the input frequency f E The interference will parasitically disturb the input frequency f of the second input signal RF2. E Carrying information.

[0093] In contrast, the first antenna A1 does not receive external electromagnetic radiation. This may be due in particular to the fact that the first antenna A1 and the second antenna A2 are located at different locations of the vehicle. Therefore, the signal RF1 does not experience any interference. Therefore, the input frequency f of the first input signal RF1 EThe information carried will not deteriorate.

[0094] The second example of the method then comprises the second to fifth steps 120, 130, 140, 150 as described above for the first example of the method. Here, the second step 120 is performed at a first instant t1.

[0095] like Figure 7 As shown, the second curve 24 has a power excess 26 on a portion of the spectrum associated with the first low injection intermediate signal IFB2. The power excess 26 corresponds to interference superimposed on the second input signal RF2 when the second antenna A2 acquires the second input signal RF2. Therefore, the first difference signal 28 has a negative power spike 30.

[0096] The second example of the method further comprises a second step B 120'. The second step B 120' is performed at a second moment t2. The first moment t1 and the second moment t2 are separated by a time interval Δt. In the second step B 120', each tuner T1, T2 also receives a corresponding first and second input signal RF1, RF2. Thus, the time interval Δt makes each input signal RF1, RF2 unchanged over the time interval Δt. In other words, the spectrum of each signal RF1, RF2 is unchanged between the first moment t1 and the second moment t2. For this purpose, the time interval Δt is less than 20ms, preferably equal to 10ms.

[0097] In a second step 120', each input signal RF1, RF2 is then tuned by the corresponding tuner T1, T2 at the same input frequency f as in the second step 120. E The second step B 120 ′ is different from the second step 120 in that a second low injection intermediate signal IFB1 is obtained based on the first input signal RF1 , and a second high injection intermediate signal IFH2 is obtained based on the second input signal RF2 .

[0098] The second example of the method then comprises, after the second step B 120', consecutive third, fourth and fifth steps B 130', 140' and 150'. The third, fourth and fifth steps B 130', 140' and 150' respectively repeat all the operations of the third, fourth and fifth steps 130, 140 and 150 as described above, but they are applied to the second low injection intermediate signal IFB1 and the second high injection intermediate signal IFH2.

[0099] Figure 7 A third power spectral density curve 32 representing the second low injection intermediate signal IFB1 and a fourth power spectral density curve 34 representing the first high injection intermediate signal IFH2 are shown, each being generated in a fourth step B 140'.

[0100] The fourth curve 34 has a power excess 26 over a portion of the spectrum associated with the second highly injected intermediate signal IFH2, which power excess 26 corresponds to interference superimposed on the second input signal RF2 when the second antenna A2 acquires it.

[0101] In contrast, here, the third curve 32 representing the second low injection intermediate signal IFB1 does not have any disturbance.

[0102] Furthermore, in a fifth step B 150', the second low injection intermediate signal IFB1 and the second high injection intermediate signal IFH2 are compared by means of the second comparator block C2. According to an alternative, the second low injection intermediate signal IFB1 and the second high injection intermediate signal IFH2 can be compared by means of the first comparator block C1. In this alternative, the central digital part 12 can include only the first comparator block C1.

[0103] The second difference signal 36 obtained in the fifth step B 150 ′ based on the second low injection intermediate signal IFB1 and the second high injection intermediate signal IFH2 therefore has a negative power peak 30 corresponding to the power excess 26 present in the fourth curve 34 .

[0104] In a sixth step B 160', the selection block S determines that the interference is superimposed on the first low injection intermediate signal IFB2 and the second high injection intermediate signal IFH2. In addition, the selection block S is also able to recognize here that the first low injection intermediate signal IFB2 and the second high injection intermediate signal IFH2 are affected by the interference in the same way. In fact, the negative power peak 30 of the first difference signal 28 is located at the same frequency as the negative power peak 30 of the second difference signal 36. It can then be inferred that the interference is due to the external electromagnetic emission 20 disturbing the acquisition of the input signal RF2.

[0105] With the help of this information, the selection block S selects one of the first high injection intermediate signal IFH1 and the second low injection intermediate signal IFB1 (both coming from the first tuner T1 ) for demodulation.

[0106] The second example of the method then comprises the seventh and eighth steps 170 and 180 as described above for the first example of the method.

[0107] Figure 8 A second case of the second example of the method is shown. The second case of the second example of the method differs from the first case of the second example of the method in that the first tuner T1 and the second tuner T2 are each also affected by the internal electromagnetic emission 20 .

[0108] In particular, the internal electromagnetic emission 20 disturbs the first tuner T1 to generate the first high injection intermediate signal IFH1, so that the interference is superimposed on the first high injection intermediate signal IFH1. Therefore, due to the internal electromagnetic emission 20 affecting the first tuner T1, the first power spectrum density curve 22 representing the first high injection intermediate signal IFH1 has a power excess 26. In contrast, the third curve 32 representing the second low injection intermediate signal IFB1 also from the first tuner T1 does not have any interference.

[0109] Similarly, the internal electromagnetic emission 20 disturbs the second tuner T2 to generate the second high injection intermediate signal IFH2, so that the interference is superimposed on the second high injection intermediate signal IFH2. Therefore, due to the internal electromagnetic emission 20 affecting the second tuner T2, the fourth power spectrum density curve 34 representing the second high injection intermediate signal IFH2 has a first power excess 26a.

[0110] Furthermore, the fourth curve 34 also has a second power excess 26b associated with interference due to external electromagnetic emissions 31 affecting the second input signal RF2. Similarly, the second curve 24 also has a power excess 26b associated with interference due to external electromagnetic emissions 31.

[0111] Thus, the first difference signal 28 includes a positive power spike 30 associated with the power excess 26 of the first curve 22 and a negative power spike 30 associated with the power excess 26b of the second curve 24. Similarly, the second difference signal 36 includes two negative power spikes 30 associated with the first and second power excesses 26a, 26b of the fourth curve 34.

[0112] The selection block S determines that interference is superimposed on the first high injection intermediate signal IFH1 based on the first difference signal 28. Furthermore, the selection block S determines that the second low injection intermediate signal IFB1 is free of any interference, since the second difference signal 36 does not include the positive power spike 30. Therefore, it can be inferred from this that the tuner T1 is affected by the internal electromagnetic emission 20.

[0113] Then, the first difference signal 28 and the second difference signal 36 each have a negative power spike 30 at the same frequency. Therefore, the selection block S determines that the first low injection intermediate signal IFB2 and the second high injection intermediate signal IFH2 include interference originating from the external electromagnetic emission 31 affecting the second input signal RF2. In addition, the selection block S determines that the second tuner T2 receives the internal electromagnetic emission 20 because the second difference signal 36 includes a negative power spike 30 that has no analog in the first difference signal 28.

[0114] According to these results, the selection block S selects the second low injection intermediate signal IFB1 for demodulation.

[0115] The first and second methods are not limited to only the above-mentioned cases but may be implemented in many cases.

[0116] Furthermore, the first example of the method and / or the second example of the method may each be implemented while the user is using the radio receiver 10. In particular, the audio stream emitted by the radio receiver is not disturbed by the implementation of one of the first and second examples of the method.

[0117] The first example of the method and / or the second example of the method can each be implemented repeatedly during use of the radio receiver 10. For example, the first example of the method and / or the second example of the method can be implemented with a test repetition equal to 1 second. Preferably, when the user selects a new input frequency f E When the first example of the method and / or the second example of the method is implemented, the load of the calculations to be performed by the central digital part 12 is thus limited.

Claims

1. A method for detecting and attenuating interference effects in a signal of a radio receiver (10) having a plurality of tuners, the method comprising the following steps: a. providing a first input signal RF1 to a first tuner (T1), b. simultaneously with step a, providing a second input signal RF2 to a second tuner (T2), c. Perform the following two actions simultaneously: using the first tuner (T1) based on the first frequency f E The first input signal RF1 is filtered up to generate a first high injection intermediate signal IFH1, and the first high injection intermediate signal IFH1 is generated by a second tuner (T2) based on the first frequency f E The up-filtered second input signal RF2 generates a first low injection intermediate signal IFB2, d. Compare the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 by the following steps: i. determining a first difference signal (28) between the power spectral density (22) of the first high injection intermediate signal IFH1 and the power spectral density (24) of the first low injection intermediate signal IFB2; and ii. analyzing the first difference signal (28), e. Selecting the better quality one of the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 for decoding by the radio receiver (10).

2. The method according to claim 1, wherein: The first input signal RF1 and the second input signal RF2 are acquired by means of a single antenna (A1).

3. The method according to claim 1, wherein: The first input signal RF1 is collected by means of a first antenna (A1), and the second input signal RF2 is collected by means of a second antenna (A2), the method comprising steps f and g, which are: f. Perform the following two actions simultaneously: by means of a first tuner (T1) based on a first frequency f E The first input signal RF1 is filtered up to generate a second low injection intermediate signal IFB1, and the second tuner (T2) is based on the first frequency f E The up-filtered second input signal RF2 generates a second high injection intermediate signal IFH2, g. Compare the second low injection intermediate signal IFB1 and the second high injection intermediate signal IFH2, Steps f and g are performed between steps d and e, step e consisting in selecting the best quality one of the first high injection intermediate signal IFH1, the first low injection intermediate signal IFB2, the second low injection intermediate signal IFB1 and the second high injection intermediate signal IFH2 for decoding by the radio receiver (10).

4. The method according to claim 3, wherein: Step c is performed at a first time t1 , and step f is performed at a second time t2 . The first time t1 and the second time t2 are separated by a time interval Δt, and the first input signal RF1 and the second input signal RF2 remain unchanged during the time interval Δt. The method according to claim 4 , wherein the time interval is equal to 10 ms.

6. The method according to any one of claims 3 to 5, wherein: Step c comprises the auxiliary step of digitizing the first high injection intermediate signal IFH1 and the first low injection intermediate signal IFB2 and, where appropriate, step f comprises the auxiliary step of digitizing the second low injection intermediate signal IFB1 and the second high injection intermediate signal IFH2.

7. The method according to any one of claims 3 to 5, wherein: Step g includes the following sub-steps: i. determining a second difference signal (36) between the power spectral density (32) of the second low injection intermediate signal IFB1 and the power spectral density (34) of the second high injection intermediate signal IFH2, ii. Analyzing the second difference signal (36).

8. The method according to claim 7, wherein: Each sub-step ii comprises evaluating the first difference signal (28) relative to an interference threshold and, where appropriate, evaluating the second difference signal (36) relative to an interference threshold.

9. The method according to claim 7, wherein: Each sub-step ii comprises evaluating the sign of the first difference signal (28) and, where appropriate, the second difference signal (36).

10. A radio receiver (10) for a motor vehicle for implementing the method according to any of the preceding claims, the radio receiver (10) having a plurality of tuners (T1), (T2), the radio receiver (10) comprising at least a first antenna (A1) and a second antenna (A2) and a central digital part (12) for signal processing.

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