Down converter and microwave signal conditioning method

Abstract

The invention relates to the technical field of microwave signal conditioning, and discloses a down converter and a microwave signal conditioning method. The down converter comprises an input port, a channel gating unit, a frequency conversion unit, an output port, a radio frequency local oscillator unit and a control unit; the frequency conversion unit is divided into four channels according to the design frequency band of the input signal, the four channels have different frequency bands and have cross frequencies, and the cross frequency range is larger than or equal to 1 GHz; the control unit controls the channel gating unit to select a channel for signal transmission according to the output signal frequency; when the frequency of the output signal is equal to that of the input signal, the input signal is filtered and amplified through the selected channel to obtain an output signal, when the frequency of the output signal is smaller than that of the input signal, a local oscillation signal is generated to the selected channel, and the input signal is filtered, converted and amplified through the selected channel to obtain the output signal. According to the invention, down-conversion and conditioning of microwave signals with limited indexes such as an ultra-wideband frequency band of 30MHz-26.5 GHz, 120dB large dynamic adjustment, 35dB low stray, 0.5 dB / 1GHz high flatness and the like can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave signal conditioning, and in particular relates to a down converter and a microwave signal conditioning method. Background Art

[0002] In order to meet the needs of exercise training and special tests, and verify the impact of various interference signals on measurement and control tasks, as a signal platform for interference equipment, it is necessary to have the ability to detect and monitor wide-band signals, and to realize real-time detection and storage of spectrum signals or electromagnetic interference signals of equipment in different frequency bands. This can be used in later exercise training and special tests to simulate the opponent's real electromagnetic interference signals, verify the performance of interference equipment, or study the spectrum characteristics of the opponent's equipment, study the performance of the opponent's equipment, and improve the actual combat confrontation capability.

[0003] With the development of communication technology, the frequency of equipment use is getting higher and higher. In order to meet the universal requirements of various frequencies and improve timeliness and fast interference performance, the interference signal platform needs to have ultra-wideband, large dynamic, low spurious, and high flatness functions. The microwave signal down-conversion module is an important part of the interference signal platform detection. Its bandwidth, power dynamic range, spurious, and flatness indicators directly affect the working efficiency of the entire platform.

[0004] Broadband usually uses a combination of frequency conversion modules of multiple frequency bands, and each frequency conversion module is selected according to the frequency band used; large dynamic adjustment requirements require external programmable attenuators, which makes the entire system larger and more complicated to control, and cannot meet timeliness. At the same time, the spurious and flatness indicators are poor, which affects the interference signal indicators during broadband interference and affects the results of training and special tests.

[0005] In response to the demand, a method for down-conversion and conditioning of microwave signals that can achieve ultra-wideband, large dynamics, low spuriousness, and high flatness is urgently needed. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies of the prior art and propose a down-converter and a microwave signal conditioning method, including four-channel division, two-stage frequency conversion, three types of filtering combinations, etc., which can realize the integration and miniaturization of the entire frequency band of 30MHz to 26.5GHz and optimize the volume and performance indicators.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a down converter, comprising an input port, a channel selection unit, a frequency conversion unit, an output port, a radio frequency local oscillator unit and a control unit; according to the principle of dividing the design frequency band of the input signal from low to high frequency, the frequency conversion unit is divided into a first channel with a first frequency band, a second channel with a second frequency band, a third channel with a third frequency band and a fourth channel with a fourth frequency band; the first frequency band and the second frequency band, the second frequency band and the third frequency band, and the third frequency band and the fourth frequency band all have crossover frequency bands, and the frequency range of the crossover frequency bands is greater than or equal to 1 GHz;

[0009] The control unit controls the channel gating unit to select one of the first channel, the second channel, the third channel or the fourth channel according to the frequency relationship between the input signal and the output signal, which is defined as the gating channel; the input signal enters the gating channel through the input port;

[0010] When the frequency of the output signal is equal to the frequency of the input signal, the input signal is filtered and amplified through the selection channel to obtain the output signal, and the output signal is output through the output port;

[0011] When the frequency of the output signal is less than the frequency of the input signal, the control unit controls the RF local oscillator unit to generate a local oscillator signal and sends it to the selection channel. The input signal is filtered, frequency-converted, and amplified by the selection channel to obtain the output signal, which is output through the output port.

[0012] As a possible implementation method, the design frequency band is 30MHz~26.5GHz; the first frequency band is 130M~1.4GHz, the second frequency band is 0.4GHz~13GHz; the third frequency band is 2GHz~18GHz; and the fourth frequency band is 17GHz~26.5GHz.

[0013] As a possible implementation method, after the second channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a second channel first frequency conversion signal; the second channel frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a second channel second frequency conversion signal; the second channel second frequency conversion signal is filtered, amplified, and attenuated to obtain an output signal, and the output signal is output through the output port.

[0014] As a possible implementation method, from the input signal to the second channel primary frequency conversion signal, it undergoes three-stage amplification, two-stage attenuation, and one-stage filtering; from the second channel primary frequency conversion signal to the second channel secondary frequency conversion signal, it undergoes two-stage filtering, one-stage amplification, and one-stage attenuation; from the second channel secondary frequency conversion signal to the output signal, it undergoes two-stage filtering, three-stage amplification, and two-stage attenuation.

[0015] As a possible implementation method, after the third channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a third channel primary frequency conversion signal; the third channel frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a third channel secondary frequency conversion signal; the third channel secondary frequency conversion signal is filtered and amplified to obtain an output signal, and the output signal is output through the output port.

[0016] As a possible implementation method, from the input signal to the third channel primary frequency conversion signal, it undergoes three-stage amplification, two-stage attenuation, and one-stage filtering; from the third channel primary frequency conversion signal to the third channel secondary frequency conversion signal, it undergoes two filtering, one-stage amplification, and one-stage attenuation; from the third channel secondary frequency conversion signal to the output signal, it undergoes one filtering and one-stage amplification.

[0017] As a possible implementation method, after the fourth channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a fourth channel first-frequency conversion signal; the fourth channel frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a fourth channel second-frequency conversion signal; the fourth channel second-frequency conversion signal is filtered and amplified to obtain an output signal, and the output signal is output through the output port.

[0018] In a second aspect, the present invention provides a microwave signal conditioning method, using the down converter provided in the first aspect, the microwave signal conditioning method comprises the following steps:

[0019] S10. The input port receives an input signal;

[0020] S11. The control unit controls the channel gating unit to select the first channel, the second channel, the third channel or any one of the third channels according to the frequency of the output signal, which is defined as the gating channel;

[0021] S12. The input signal enters the selection channel, is filtered and amplified by the selection channel, or, is filtered, amplified, and frequency-converted by the selection channel to obtain the output signal, and the output signal is output through the output port.

[0022] As a possible implementation method, S12 specifically includes the following steps:

[0023] When the frequency of the output signal is equal to the frequency of the input signal, the input signal is filtered and amplified by the selection channel to obtain the output signal, and the output signal is output through the output port;

[0024] When the frequency of the output signal is greater than the frequency of the input signal, the control unit controls the RF local oscillator unit to generate a local oscillator signal and sends it to the selection channel. The input signal is filtered, frequency-converted, and amplified by the selection channel to obtain the output signal, which is output through the output port.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The down converter provided by the present invention divides the ultra-wideband microwave signal into four channels with different frequency bands, and the four channels have cross-frequency between each other, and the range of the cross-frequency is greater than or equal to 1GHz, which can ensure that any frequency point meets the use requirements of the 1GHz ultra-wideband, and realize full coverage of signals within the 1GHz bandwidth while realizing down-conversion of ultra-wideband signals.

[0027] 2. The down converter provided by the present invention has multi-stage amplification and attenuation for each channel, thus achieving 120dB power large dynamic range adjustment.

[0028] 3. The down converter provided by the present invention adopts a combination of multiple types of filters, which can make full use of the different characteristics of each type of filter to realize filtering processing of RF input signals, primary frequency conversion signals and secondary frequency conversion signals in the channel, effectively suppressing out-of-band spurious indicators, and at the same time achieving a high flatness indicator of the entire frequency band of <0.5dB / 1GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 Schematic diagram of the structure of a down converter in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the first channel in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the second channel in an embodiment of the present invention;

[0033] Figure 4 Schematic diagram of suppressing the first spurious frequency in the second channel in an embodiment of the present invention;

[0034] Figure 5 Schematic diagram of suppressing the second spurious frequency in the second channel in an embodiment of the present invention

[0035] Figure 6 This is a schematic diagram of a third channel in an embodiment of the present invention;

[0036] Figure 7Schematic diagram of spurious frequency suppression in the third channel in an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the fourth channel in an embodiment of the present invention;

[0038] Fig. 9 Schematic diagram of suppressing the first spurious frequency in the fourth channel in an embodiment of the present invention;

[0039] Fig.10 Schematic diagram of suppressing the second spurious frequency in the fourth channel in an embodiment of the present invention;

[0040] Fig.11 The figure is a flow chart of a microwave signal conditioning method in an embodiment of the present invention.

[0041] Reference numerals

[0042] 1-input port, 2-channel gating unit;

[0043] 3-frequency conversion unit, 30-first channel, 3000-first filter, 3001-first attenuator, 3002-first amplifier, 3003-second attenuator, 3004-second amplifier, 3005-third attenuator, 3006-third amplifier, 3007-second filter, 3008-fourth attenuator, 3009-fourth amplifier;

[0044] 31-second channel, 3100-fifth amplifier, 3101-fifth attenuator, 3102-sixth amplifier, 3103-sixth attenuator, 3104-seventh amplifier, 3105-first filter combination, 31050-filter one, 31051-filter two, 31052-filter three, 3106-first mixer, 3107-third filter, 3108-eighth amplifier, 3109-fourth filter, 3110-seventh attenuator, 3111-second mixer, 3112-fifth filter, 3113-ninth amplifier, 3114-eighth attenuator, 3115-tenth amplifier, 3116-sixth filter, 3117-ninth attenuator, 3118-eleventh amplifier, 3119-first narrowband filter, 3120-second narrowband filter;

[0045] 32-third channel, 3200-twelfth amplifier, 3201-tenth attenuator, 3202-thirteenth amplifier, 3203-eleventh attenuator, 3204-fourteenth amplifier, 3205-second filter combination, 32050-fourth filter, 32051-five filter, 32052-sixth filter, 32053-seventh filter, 32054-eighth filter, 32055-nine filter, 32056-tenth filter, 3206-third mixer, 3207-seventh filter, 3208-fifteenth amplifier, 3209-eighth filter, 3210-twelfth attenuator, 3211-fourth mixer, 3212-ninth filter, 3213-sixteenth amplifier, 3214-thirteenth attenuator, 3215-seventeenth amplifier, 3216-fourteenth attenuator, 3217-eighteenth amplifier, 3218-tenth filter;

[0046] 33-the fourth channel, 3300-the nineteenth amplifier, 3301-the fifteenth attenuator, 3302-the twentieth amplifier, 3303-the sixteenth attenuator, 3304-the twenty-first amplifier, 3305-the third filter combination, 33050-the eleventh filter, 33051-the twelveth filter, 33052-the thirteenth filter, 33053-the fourteenth filter, 3306-the fifth mixer, 3307-the eleventh filter, 3308-the twenty-second amplifier, 3309-the twelfth filter, 3310-the seventeenth attenuator, 3311-the sixth mixer, 3312-the thirteenth filter, 3313-the twenty-third amplifier, 3314-the eighteenth attenuator, 3315-the twenty-fourth amplifier, 3316-the nineteenth attenuator, 3317-the twenty-fifth amplifier, 3318-the fourteenth filter;

[0047] 4-output port, 5-RF local oscillator unit, 6-control unit. DETAILED DESCRIPTION

[0048] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0049] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0050] In the present invention, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. The following at least one item (items) or similar expressions thereof refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (items) of a, b or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0051] The invention provides a microwave signal down-conversion and conditioning method capable of realizing ultra-wideband, large dynamic, low spurious and high flatness.

[0052] In a first aspect, the present invention provides a down converter, see Figure 1 , including an input port 1, a channel selection unit 2, a frequency conversion unit 3, an output port 4, a radio frequency local oscillator unit 5 and a control unit 6;

[0053] The radio frequency local oscillator unit 5 has two digital frequency synthesizer chips with the same functions. The digital frequency synthesizer is controlled by the control unit 6 and is used to generate the local oscillator signal required for the frequency conversion of the channel gating unit according to the input signal.

[0054] According to the principle of dividing the design frequency band of the output signal from low to high frequency, the frequency conversion unit 3 is divided into a first channel 30 with a first frequency band, a second channel 31 with a second frequency band, a third channel 32 with a third frequency band, and a fourth channel 33 with a fourth frequency band; the first frequency band and the second frequency band, the second frequency band and the third frequency band, and the third frequency band and the fourth frequency band all have cross-frequency bands, and the range of the cross-frequency bands is greater than or equal to 1 GHz.

[0055] As a possible implementation method, the design frequency band is 30MHz~26.5GHz; the first frequency band is 130M~1.4GHz, the second frequency band is 0.4GHz~13GHz; the third frequency band is 2GHz~18GHz; the fourth frequency band is 17GHz~26.5GHz, and the frequency range of the cross-bands of the four frequency bands is ≥1GHz, which can ensure that the bandwidth of any frequency point is ≥1GHz, and achieve full coverage of signals within the 1GHz bandwidth.

[0056] See also Figure 1 , the control unit 6 controls the channel gating unit 2 to select one of the first channel 30, the second channel 31, the third channel 32 or the fourth channel 33 according to the frequency relationship between the input signal and the output signal, which is defined as the gating channel; the input signal enters the gating channel through the input port 1;

[0057] The present invention can realize the down-conversion and conditioning of microwave signals in the ultra-wideband frequency band of 30MHz to 26.5GHz, divide the four channels with different frequency bands according to the principle of frequency from low to high, and the control unit controls the channel selection unit to select the channel according to the frequency relationship between the input signal and the output signal, so as to conveniently switch the channels and ensure that the selected channel and the local oscillator frequency correspond to the final output frequency, thereby realizing accurate and reliable switching and output of the radio frequency signal.

[0058] When the frequency of the output signal is equal to the frequency of the input signal, the input signal is filtered and amplified through the selection channel to obtain the output signal, and the output signal is output through the output port;

[0059] When the frequency of the output signal is less than the frequency of the input signal, the control unit 6 controls the RF local oscillator unit 5 to generate a local oscillator signal and sends it to the selection channel. The input signal is filtered, frequency-converted, and amplified by the selection channel to obtain the output signal, which is output through the output port.

[0060] See also Figure 2 As a possible implementation method, the first channel 30 is a selection channel when the frequencies of the input signal and the output signal are equal; the first channel 30 is a channel with four-stage attenuation and four-stage amplification functions, and in the propagation direction of the signal, the attenuator and the amplifier are arranged crosswise in sequence; the first channel 30 is equipped with filters before the first stage attenuation and before the fourth stage attenuation.

[0061] For example, see Figure 2 In the transmission direction of the input signal, the first channel 30 includes a first filter 3000, a first attenuator 3001, a first amplifier 3002, a second attenuator 3003, a second amplifier 3004, a third attenuator 3005, a third amplifier 3006, a second filter 3007, a fourth attenuator 3008 and a fourth amplifier 3009 connected in sequence.

[0062] Exemplarily, the four-stage attenuators in the first channel 30 are all digitally controlled attenuators. The use of the four-stage digitally controlled attenuator and the four-stage amplifier can achieve a large dynamic adjustment of 110 dB while reducing the link insertion loss when there is no adjustment.

[0063] As a possible implementation method, after the second channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a second channel first frequency conversion signal; the second channel frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a second channel second frequency conversion signal; the second channel second frequency conversion signal is filtered, amplified, and attenuated to obtain an output signal, and the output signal is output through the output port.

[0064] As a possible implementation method, from the input signal to the second channel primary frequency conversion signal, it undergoes three-stage amplification, two-stage attenuation, and one-stage filtering; from the second channel primary frequency conversion signal to the second channel secondary frequency conversion signal, it undergoes two-stage filtering, one-stage amplification, and one-stage attenuation; from the second channel secondary frequency conversion signal to the output signal, it undergoes two-stage filtering, three-stage amplification, and two-stage attenuation.

[0065] See also Figure 3 In the transmission direction of the input signal, the second channel 31 includes a fifth amplifier 3100, a fifth attenuator 3101, a sixth amplifier 3102, a sixth attenuator 3103, a seventh amplifier 3104, a first filter combination 3105, a first mixer 3106, a third filter 3107, an eighth amplifier 3108, a fourth filter 3109, a seventh attenuator 3110, a second mixer 3111, a fifth filter 3112, a ninth amplifier 3113, an eighth attenuator 3114, a tenth amplifier 3115, a sixth filter 3116, a ninth attenuator 3117, and an eleventh amplifier 3118 connected in sequence.

[0066] As an example, the third filter 3107 and the sixth filter 3116 in the second channel 31 are cavity filters, and the other filters are planar filters or MEMS filters. The combination of planar filters, MEMS filters and cavity filters can fully utilize the different characteristics of the two types of filters. For example, the planar filter has low stopband suppression and poor rectangular coefficient; the MEMS filter has high insertion loss and good stopband suppression; the cavity filter has low insertion loss, good stopband suppression and high frequency accuracy; it realizes filtering processing of the RF input signal, the second channel primary frequency conversion signal and the second channel secondary frequency conversion signal, and effectively reduces out-of-band spurious.

[0067] See also Figure 3, wherein the first filter combination 3105 is composed of three filters with different bandwidths to achieve the bandwidth range of the second channel 31 matching and filter out the out-of-band spurious; the bandwidths of the three filters are: filter one 31050 (0.4-1.7GHz), filter two 31051 (0.7-2.2GHz), filter three 31052 (1.2-3GHz); the performance indicators of the first filter combination 3105 are shown in Table 1:

[0068] Table 1 Performance indicators of the first filter combination

[0069]

[0070] See also Figure 3 to Figure 4 The first spurious frequency of the second channel 31 is located at the mixing component of the second channel primary frequency conversion signal and the first local oscillator signal. This frequency point is suppressed by the spurious suppression index of the first mixer 3106 and the out-of-band suppression index of the first narrowband filter 3119 before the second mixer 3111. The first mixer 3106 suppresses 30dB, and the first narrowband filter 3119 suppresses 15dB, which together produce 45dB suppression.

[0071] See also Figure 3 and Figure 5 The second spurious frequency of the second channel 31 is located at the image component of the mixing of the first frequency conversion signal of the second channel and the first local oscillator signal. This frequency point is suppressed by the out-of-band suppression index of the second narrowband filter 3120 before the first mixer 3106 and the second harmonic suppression index of the first mixer 3106. The first mixer 3106 suppresses 10dB, and the second narrowband filter 3120 suppresses 25dB, which together produce 35dB suppression.

[0072] The second channel 31 is provided with a total of five digitally controlled attenuators, which can obtain a 120dB power attenuation and achieve a maximum 120dB power dynamic range adjustment. After the input signal is filtered, attenuated and amplified by each device in the second channel 31, the out-of-band spurious of the final output signal is further reduced.

[0073] As a possible implementation method, after the third channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a third channel primary frequency conversion signal; the third channel frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a third channel secondary frequency conversion signal; the third channel secondary frequency conversion signal is filtered and amplified to obtain an output signal, and the output signal is output through the output port.

[0074] As a possible implementation method, from the input signal to the third channel primary frequency conversion signal, it undergoes three-stage amplification, two-stage attenuation, and one-stage filtering; from the third channel primary frequency conversion signal to the third channel secondary frequency conversion signal, it undergoes two filtering, one-stage amplification, and one-stage attenuation; from the third channel secondary frequency conversion signal to the output signal, it undergoes one filtering and one-stage amplification.

[0075] See also Figure 6 In the transmission direction of the input signal, the third channel 32 includes a twelfth amplifier 3200, a tenth attenuator 3201, a thirteenth amplifier 3202, an eleventh attenuator 3203, a fourteenth amplifier 3204, a second filter combination 3205, a third mixer 3206, a seventh filter 3207, a fifteenth amplifier 3208, an eighth filter 3209, a twelfth attenuator 3210, a fourth mixer 3211, a ninth filter 3212, a sixteenth amplifier 3213, a thirteenth attenuator 3214, a seventeenth amplifier 3215, a fourteenth attenuator 3216, an eighteenth amplifier 3217, and a tenth filter 3218 connected in sequence.

[0076] As an example, the seventh filter 3207 and the tenth filter 3218 in the third channel 32 are cavity filters, and the other filters are planar filters or MEMS filters. The combination of planar filters, MEMS filters and cavity filters can fully utilize the different characteristics of each type of filters. For example, the planar filter has low stopband suppression and poor rectangular coefficient; the MEMS filter has high insertion loss and good stopband suppression; the cavity filter has low insertion loss, good stopband suppression and high frequency accuracy; it realizes filtering processing of the RF input signal, the third channel primary frequency conversion signal and the third channel secondary frequency conversion signal, and effectively reduces out-of-band spurious.

[0077] See also Figure 6 The second filter combination 3205 is composed of seven filter combinations with different bandwidths to achieve the matching bandwidth range of the third channel 32 and filter out the out-of-band spurious; the bandwidths of the seven filters are: filter four 32050 (1.9-3.2GHz), filter five 32051 (2.2-3.7GHz), filter six 32052 (2.7-4.6GHz), filter seven 32053 (3.6-6.1GHz), filter eight 32054 (5.1-8.9GHz), filter nine 32055 (7.9-13.8GHz), filter ten 32056 (12.8-18GHz); the performance indicators of the second filter combination 3205 are shown in Table 2:

[0078] Table 2 Performance indicators of the second filter combination

[0079]

[0080] See also Figure 6 to Figure 7 The nearest spurious frequency of the third channel 32 is located at the mixing image component of the RF frequency and the first local oscillator signal and the local oscillator harmonic of the fourth mixer 3211. This frequency point is jointly suppressed by the seventh filter 3207 after the third mixer 3206 and the spurious suppression index of the fourth mixer 3211. The seventh filter 3207 suppresses 30dB and the fourth mixer 3211 suppresses 10dB, which together produce 40dB suppression.

[0081] The third channel 32 is provided with a total of five digital controlled attenuators, which can obtain a 120dB power attenuation and achieve a maximum 120dB power dynamic range adjustment. After the input signal is filtered, attenuated and amplified by each device in the third channel 32, the out-of-band spurious of the final output signal is further reduced.

[0082] As a possible implementation method, after the fourth channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a fourth channel first-frequency conversion signal; the fourth channel frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a fourth channel second-frequency conversion signal; the fourth channel second-frequency conversion signal is filtered and amplified to obtain an output signal, and the output signal is output through the output port.

[0083] See also Figure 8 In the transmission direction of the input signal, the fourth channel 33 includes a nineteenth amplifier 3300, a fifteenth attenuator 3301, a twentieth amplifier 3302, a sixteenth attenuator 3303, a twenty-first amplifier 3304, a third filter combination 3305, a fifth mixer 3306, an eleventh filter 3307, a twenty-second amplifier 3308, a twelfth filter 3309, a seventeenth attenuator 3310, a sixth mixer 3311, a thirteenth filter 3312, a twenty-third amplifier 3313, an eighteenth attenuator 3314, a twenty-fourth amplifier 3315, a nineteenth attenuator 3316, a twenty-fifth amplifier 3317, and a fourteenth filter 3318 connected in sequence.

[0084] As an example, the eleventh filter 3307 and the fourteenth filter 3318 in the fourth channel 33 are cavity filters, and the other filters are planar filters or MEMS filters. The combination of planar filters, MEMS filters and cavity filters can fully utilize the different characteristics of each type of filters. For example, the planar filter has low stopband suppression and poor rectangular coefficient; the MEMS filter has high insertion loss and good stopband suppression; the cavity filter has low insertion loss, good stopband suppression and high frequency accuracy; it realizes filtering processing of the RF input signal, the fourth channel primary frequency conversion signal and the fourth channel secondary frequency conversion signal, and effectively reduces out-of-band spurious.

[0085] See also Figure 8 The third filter combination 3305 is composed of four filter combinations with different bandwidths to achieve the matching bandwidth range of the fourth channel 33 and filter out the out-of-band spurious; the bandwidths of the four filters are: filter eleven 33050 (16-19 GHz), filter twelve 33051 (28-22 GHz), filter thirteen 33052 (21-25 GHz), filter fourteen 33053 (24-26.5 GHz); the performance indicators of the third filter combination 3305 are shown in Table 3:

[0086] Table 3 Performance indicators of the third filter combination

[0087]

[0088] See also Figures 8 to 9 The nearest spurious frequency of the fourth channel 33 is located at the mixing component of the fourth channel secondary frequency conversion signal and the first local oscillator signal. This frequency point is suppressed by the spurious suppression index of the fifth mixer 3306, and the fifth mixer 3306 is suppressed by 35dB.

[0089] See also Figure 8 and Fig.10 Another spurious frequency of the fourth channel 33 is located at the mixing image component of the fourth channel first frequency conversion signal and the first local oscillator signal and the harmonic generation of the sixth mixer 3311. This frequency point is jointly suppressed by the spurious suppression index of the fifth mixer 3306 and the mixing harmonic suppression index of the sixth mixer 3311. The sixth mixer 3311 suppresses 25dB, and the thirteenth filter 3312 suppresses 15dB, which together produce 40dB suppression.

[0090] The fourth channel 33 is provided with five-level digital controlled attenuators, which can obtain 120dB power attenuation and achieve a maximum 120dB power dynamic range adjustment. After the input signal is filtered, attenuated and amplified by each device in the fourth channel 33, the out-of-band spurious of the final output signal is further reduced.

[0091] See also Figure 2 , Figure 3 , Figure 6 and Figure 8 The present invention is provided with a switch on each channel main link, and switches are also provided before and after each filter combination, which can more flexibly select the selection channel, and can select the filter to be used according to the different performance indicators of each filter. It is easy to use and highly flexible. In addition, in order to ensure the flatness of the signal within the frequency band, an equalizer (not shown in the figure) is designed in the link to adjust the flatness of the link.

[0092] In a second aspect, the present invention provides a microwave signal conditioning method, using the down converter provided in the first aspect, see Fig.11 , the microwave signal conditioning method comprises the following steps:

[0093] S10. The input port receives an input signal;

[0094] S11. The control unit controls the channel gating unit to select any one of the first channel, the second channel, the third channel or the fourth channel according to the frequency of the output signal, which is defined as the gating channel;

[0095] S12. The input signal enters the selection channel, is filtered and amplified by the selection channel, or, is filtered, amplified, and frequency-converted by the selection channel to obtain the output signal, and the output signal is output through the output port.

[0096] As a possible implementation method, S12 specifically includes the following steps:

[0097] When the frequency of the output signal is equal to the frequency of the input signal, the input signal is filtered and amplified through the selection channel to obtain the output signal, and the output signal is output through the output port;

[0098] When the frequency of the output signal is greater than the frequency of the input signal, the control unit controls the RF local oscillator unit to generate a local oscillator signal and send it to the selection channel. The input signal is filtered, frequency-converted, and amplified by the selection channel to obtain the output signal, which is output through the output port.

[0099] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the drawings, etc. In the specification, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the specification. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0100] Although the present invention has been described in conjunction with specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations if they fall within the scope of the present invention and its equivalents.

Claims

1. A down converter, characterized in that: It includes an input port, a channel selection unit, a frequency conversion unit, an output port, a radio frequency local oscillator unit and a control unit; according to the design frequency band of the input signal and the principle of dividing the frequency from low to high, the frequency conversion unit is divided into a first channel with a first frequency band, a second channel with a second frequency band, a third channel with a third frequency band and a fourth channel with a fourth frequency band; the first frequency band and the second frequency band, the second frequency band and the third frequency band, and the third frequency band and the fourth frequency band all have cross-frequency bands, and the frequency range of the cross-frequency bands is greater than or equal to 1 GHz; The control unit controls the channel gating unit to select one of the first channel, the second channel, the third channel or the fourth channel according to the frequency relationship between the input signal and the output signal, which is defined as the gating channel; the input signal enters the gating channel through the input port; When the frequency of the output signal is equal to the frequency of the input signal, the input signal is filtered and amplified by the selection channel to obtain the output signal, and the output signal is output through the output port; when the frequency of the output signal is less than the frequency of the input signal, the control unit controls the RF local oscillator unit to generate a local oscillator signal and sends it to the selection channel, and the input signal is filtered, frequency converted, and amplified by the selection channel to obtain the output signal, and the output signal is output through the output port.

2. The down converter according to claim 1, characterized in that: The designed frequency band is 30MHz to 26.5GHz; the first frequency band is 130M to 1.4GHz, the second frequency band is 0.4GHz to 13GHz; the third frequency band is 2GHz to 18GHz; and the fourth frequency band is 17GHz to 26.5GHz.

3. The down converter according to claim 1, characterized in that: The first channel is a selection channel when the frequencies of the input signal and the output signal are equal; the first channel is a channel with four-level attenuation and four-level amplification functions, and in the propagation direction of the signal, the attenuator and the amplifier are arranged crosswise in sequence; the first channel is provided with filters before the first level attenuation and before the fourth level attenuation.

4. The down converter according to claim 1, characterized in that: After the second channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a second channel primary frequency conversion signal; the second channel frequency conversion signal is filtered, amplified, and attenuated, and then mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a second channel secondary frequency conversion signal; the second channel secondary frequency conversion signal is filtered, amplified, and attenuated to obtain an output signal, and the output signal is output through the output port.

5. The down converter according to claim 4, characterized in that: From the input signal to the first frequency conversion signal of the second channel, it undergoes three-stage amplification, two-stage attenuation, and one-stage filtering; from the first frequency conversion signal of the second channel to the second frequency conversion signal of the second channel, it undergoes two-stage filtering, one-stage amplification, and one-stage attenuation; from the second channel second frequency conversion signal to the output signal, it undergoes two-stage filtering, three-stage amplification, and two-stage attenuation.

6. The down converter according to claim 1, characterized in that: After the third channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a third channel primary frequency conversion signal; the third channel frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a third channel secondary frequency conversion signal; the third channel secondary frequency conversion signal is filtered and amplified to obtain an output signal, and the output signal is output through the output port.

7. The down converter according to claim 6, characterized in that: From the input signal to the first frequency conversion signal of the third channel, it undergoes three-stage amplification, two-stage attenuation, and one-stage filtering; from the first frequency conversion signal of the third channel to the second frequency conversion signal of the third channel, it undergoes two-stage filtering, one-stage amplification, and one-stage attenuation; from the second frequency conversion signal of the third channel to the output signal, it undergoes one-stage filtering and one-stage amplification.

8. The down converter according to claim 1, characterized in that: After the fourth channel receives the input signal, it is amplified, attenuated, filtered, and mixed with the first local oscillator signal provided by the RF local oscillator unit to obtain a fourth channel primary frequency conversion signal; the fourth channel sequential frequency conversion signal is filtered, amplified, attenuated, and mixed with the second local oscillator signal provided by the RF local oscillator unit to obtain a fourth channel secondary frequency conversion signal; the fourth channel secondary frequency conversion signal is filtered and amplified to obtain an output signal, and the output signal is output through the output port.

9. A microwave signal conditioning method, characterized in that: Using the down converter according to any one of claims 1 to 8, the microwave signal conditioning method comprises the following steps: S10. The input port receives an input signal; S11. The control unit controls the channel gating unit to select any one of the first channel, the second channel, the third channel or the fourth channel according to the frequency of the output signal, which is defined as the gating channel; S12. The input signal enters the selection channel, is filtered and amplified by the selection channel, or, is filtered, amplified, and frequency-converted by the selection channel to obtain the output signal, and the output signal is output through the output port.

10. The microwave signal conditioning method according to claim 9, characterized in that: The S12 specifically includes the following steps: When the frequency of the output signal is equal to the frequency of the input signal, the input signal is filtered and amplified by the selection channel to obtain the output signal, and the output signal is output through the output port; When the frequency of the output signal is greater than the frequency of the input signal, the control unit controls the RF local oscillator unit to generate a local oscillator signal and sends it to the selection channel. The input signal is filtered, frequency-converted, and amplified by the selection channel to obtain an output signal, which is output through the output port.

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