A multi-octave wideband frequency conversion assembly

Abstract

The application discloses a multi-octave wideband frequency conversion assembly, which comprises a frequency conversion circuit, an amplitude control circuit and a switch filter set, wherein the frequency conversion circuit expands the input radio frequency to an intermediate frequency signal through two local oscillator frequency points for the input radio frequency signal and outputs the intermediate frequency signal to the amplitude control circuit; the amplitude control circuit adjusts the amplitude of the intermediate frequency signal output by the frequency conversion circuit; the switch filter set filters the signal output by the amplitude control circuit through a multi-path filter set, filters out harmonics and stray signals, and performs amplitude correction to obtain a multi-octave intermediate frequency output signal. The 3-4GHz signal is expanded to a ten-octave signal of 0.2-2GHz which can be directly processed by a digital circuit through the two local oscillator frequency points of 4 / 5GHz, the output power reaches 10dBm, the harmonic suppression reaches more than 48dBc, the power flatness reaches ±1dB, the dynamic range reaches more than 60dB, and the step is only 0.25dB.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microwave radar technology, in particular to a multi-octave wideband frequency conversion assembly. BACKGROUND

[0002] The microwave frequency converter plays an extremely important role in the field of microwave detection. With the increasingly tense use of frequency band resources, various different electromagnetic interferences are increased in the communication environment, and the requirements for information detection radar tend to develop in the direction of high integration and high performance. In terms of high integration, the technology of hybrid integrated circuit is used to integrate various high-performance chips such as mixers, low-noise amplifiers, switches and digitally controlled attenuators, which are made of various semiconductor device processes, to meet the needs of miniaturization and mobility of the assembly. In terms of high performance, the frequency width covered by the frequency conversion assembly is becoming wider and wider, especially in the development of high linearity, large dynamic range, high sensitivity and high resolution. The wideband frequency conversion assembly converts the wide frequency domain signal to a lower frequency for sampling processing, which is a key component of information detection radar. It is a challenging task to realize a low-cost, high-performance wireless radio frequency receiver terminal.

[0003] The wideband frequency conversion system for the detection radar receiver has a relatively mature scheme of a radio frequency front-end module working in the 0.2-2GHz frequency band. Currently, the main problems of this scheme are concentrated on the difficulties of spurious suppression and harmonic suppression under wideband conditions. SUMMARY

[0004] The purpose of the present application is to provide a multi-octave wideband frequency conversion assembly with excellent flatness index and harmonic characteristics, which converts the input signal 3-4GHz radio frequency signal to 0.2-2GHz.

[0005] The technical solution to achieve the purpose of the present application is: a multi-octave wideband frequency conversion assembly, comprising a frequency conversion circuit, an amplitude control circuit and a switch filter bank, wherein:

[0006] The frequency conversion circuit, for the input radio frequency signal, expands the frequency to an intermediate frequency signal through two local oscillator frequency points and outputs to the amplitude control circuit;

[0007] The amplitude control circuit adjusts the amplitude of the intermediate frequency signal output by the frequency conversion circuit;

[0008] The switch filter bank filters out harmonics and spurs by segmenting and filtering the signal output by the amplitude control circuit through a multi-path filter bank, and performs amplitude correction to obtain a multi-octave intermediate frequency output signal.

[0009] The present application has the following remarkable features compared with the prior art: (1) the input 3-4GHz 1GHz bandwidth signal is down-converted to 0.2-2GHz by using an eight-way switch filter bank, so that the frequency bandwidth is expanded by ten times; (2) the amplitude is adjusted by using a digital attenuator, a switch filter bank, an amplifier and an equalizer, and meanwhile the matching between the links and the harmonic characteristics are adjusted, so that excellent flatness index and harmonic characteristics are obtained; (3) the total dynamic range reaches 60dB, and the attenuation step is only 0.25dB; the output power reaches 10dBm, and the harmonic suppression is more than 48dBc. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is the component principle circuit block diagram of the present application.

[0011] Figure 2 is the frequency conversion circuit block diagram of the present application.

[0012] Figure 3 is the amplitude control circuit block diagram of the present application.

[0013] Figure 4 is the eight-way switch filter bank block diagram of the present application. DETAILED DESCRIPTION

[0014] The present application relates to a multi-times wideband frequency conversion component, which is composed of two input ports and two output ports. The component is composed of a mixing part circuit, an amplitude control part circuit and an eight-way switch filter bank, so that the 3-4GHz signal is expanded to a ten-times signal of 0.2-2GHz by using two local oscillator frequency points of 4 / 5GHz, which can be directly processed by a digital circuit. The link uses a four-stage amplifier, three digital attenuators and an equalizer of each branch to adjust the amplitude of the final output signal, and meanwhile the wideband signal is segmented and filtered by an eight-way filter bank to ensure good harmonic performance and stray performance, so that the wideband frequency conversion component with the output power of 10dBm, the harmonic suppression of more than 48dBc, the power flatness of ±1dB, the dynamic range of more than 60dB and the step of only 0.25dB is finally realized.

[0015] Combining Figures 1-4 , the present application is a multi-times wideband frequency conversion component, which comprises a frequency conversion circuit 1, an amplitude control circuit 2 and a switch filter bank 3, wherein:

[0016] The frequency conversion circuit 1 expands the frequency of the input radio frequency signal to an intermediate frequency signal by using two local oscillator frequency points, and outputs the intermediate frequency signal to the amplitude control circuit 2;

[0017] The amplitude control circuit 2 adjusts the amplitude of the intermediate frequency signal output by the frequency conversion circuit 1.

[0018] The switch filter group 3 filters the signal outputted by the amplitude control circuit 2 through the multi-path filter group to filter out harmonics and spurs, and performs amplitude correction to obtain a multi-octave intermediate frequency output signal.

[0019] Further, the input radio frequency signal of the frequency conversion circuit 1 is 3-4GHz, and the corresponding radio frequency signal 3.1-3.8GHz is converted to 0.2-0.9GHz by using a 4GHz local oscillator signal, then the local oscillator signal is switched to 5GHz, and the 3.1-4.1GHz is converted to 0.9-2GHz; the switch filter group 3 filters out the harmonics and spurs of the output intermediate frequency signal with a span of ten octaves, including one 0.2-2GHz intermediate frequency signal and one 0.2-2GHz intermediate frequency signal for self-checking.

[0020] Further, the frequency conversion circuit 1 is specifically as follows:

[0021] The input radio frequency signal is inputted to the radio frequency port of the mixer 11 after being adjusted in power by the first attenuator 10; the local oscillator signal is improved to a set power level by the first amplifier 14, then the harmonics of the local oscillator signal are filtered out by the second filter 15, and then the power is adjusted and the link level is matched by the third attenuator 16, and then the local oscillator input end of the mixer 11 is inputted; the obtained intermediate frequency signal is outputted to the second attenuator 12 by the mixer 11, and finally the mirror frequency signal is filtered out by the first filter 13 to obtain the final intermediate frequency signal, which is outputted to the amplitude control circuit 2.

[0022] Further, the amplitude control circuit 2 includes a second amplifier 20, a first digital attenuator 21, a fourth attenuator 22, a third amplifier 23, a second digital attenuator 24, a fifth attenuator 25, a fourth amplifier 26, a third digital attenuator 27, a fifth amplifier 28, and a first equalizer 29 connected in sequence.

[0023] The intermediate frequency signal outputted by the frequency conversion circuit 1 is first passed through the second amplifier 20, then through the first digital attenuator 21, then through the fourth attenuator 22 to adjust the signal harmonic characteristics of the link, then through the third amplifier 23 to amplify the signal, then through the second digital attenuator 24, then through the fifth attenuator 25 to adjust the signal harmonic characteristics of the link, then through the fourth amplifier 26 to amplify the signal, then through the third digital attenuator 27, then through the fifth amplifier 28 to reach the maximum power value, and finally through the first equalizer 29 to perform amplitude correction, and then outputted to the switch filter group 3.

[0024] Further, the switch filter set 3 comprises a first single-pole N-throw switch 30, a single-pole single-throw switch 31, a third filter 32, a second equalizer 33, a second single-pole N-throw switch 34, a third equalizer 35, a coupler 36, N being a natural number greater than 2.

[0025] The amplitude-corrected signal output by the amplitude control circuit 2 is divided into N paths through the first single-pole N-throw switch 30; each path comprises a set of single-pole single-throw switches 31, a third filter 32, and a second equalizer 33 connected in sequence, the single-pole single-throw switches 31 being used to increase the isolation between channels, and the second equalizer 33 being used to correct the amplitude of the divided radio frequency signals; the N amplitude-corrected signals are combined into a full-band signal through the second single-pole N-throw switch 34, the third equalizer 35 performs overall amplitude correction on the full-band signal, and the signal is output to the coupler 36, which divides the received signal into two paths, one of which is directly output, and the other is used as a self-checking signal.

[0026] Further, the local oscillator signal of 4 GHz is used to convert the corresponding radio frequency signal of 3.1-3.8 GHz to 0.2-0.9 GHz, then the local oscillator signal is switched to 5 GHz, and the radio frequency signal of 3.1-4.1 GHz is converted to 0.9-2 GHz, as shown in Table 1:

[0027] Table 1

[0028]

[0029]

[0030] Further, the step of the first digital attenuator 21 is 0.25 dB, and the total attenuation is 15.5 dB; the step of the second digital attenuator 24 is 0.5 dB, and the total attenuation is 31.5 dB; the step of the third digital attenuator 27 is 0.5 dB, and the total attenuation is 31.5 dB.

[0031] Further, the value of N is 8, and the first single-pole N-throw switch 30 and the second single-pole N-throw switch 34 are both single-pole eight-throw switches.

[0032] Further, the coupler 36 is a 10 dB coupler.

[0033] Further, the input power of the radio frequency signal of the entire wideband frequency conversion assembly is -8±1 dBm, the power of the local oscillator signal is 0±3 dBm, the output signal power is 9-11 dBm, the in-band flatness of the receiving gain is ≤±1.5 dB, the output signal harmonic is 0.2-0.38 GHz≤-48 dBc, 0.38-2 GHz≤-50 dBc, the output signal spur is ≥50 dBc, and the amplitude control range is ≥60 dB.

[0034] The working bandwidth of the broadband frequency conversion assembly covers 0.2-2GHz, and the frequency span reaches ten times. The main functions of the product are: 1) the input 3-4GHz 1GHz bandwidth signal is down-converted to 0.2-2GHz, and the frequency bandwidth is expanded to ten times; 2) the amplitude is adjusted through a digital control attenuator, a switch filter group, an amplifier and an equalizer, and the matching between the links and the harmonic characteristics are adjusted to obtain excellent flatness index and harmonic characteristics.

[0035] The main indexes describing the performance of the product are: 1) spurious suppression; 2) output power; 3) dynamic range; 4) harmonic suppression degree, 5) output power flatness and the like.

[0036] The technical solution adopted by the application has the following advantages:

[0037] 1) a multi-stage digital control expansion dynamic range is adopted, and the total dynamic range reaches 60dB, and the attenuation step is only 0.25dB;

[0038] 2) eight switch filter groups are adopted to segment the signal, and the working bandwidth span reaches ten times;

[0039] 3) the output power reaches about 10dBm, and the harmonic suppression reaches more than 48dBc;

[0040] 4) the link adopts a multi-stage equalizer for amplitude equalization, and realizes the low fluctuation characteristics of ±1dB within a wide frequency span.

[0041] The application will be further described in detail below in combination with the drawings and embodiments.

[0042] Embodiment

[0043] The embodiment provides a multi-span broadband frequency conversion assembly, which combines Figure 1 Briefly, the principle block diagram of the assembly is analyzed. The radio frequency input signal is 3-4GHz, a 4GHz local oscillator signal is adopted to convert the corresponding radio frequency signal 3.1-3.8GHz to 0.2-0.9GHz, then the local oscillator signal is switched to 5GHz, and then 3.1-4.1GHz is converted to 0.9-2GHz. The specific frequency conversion relationship is shown in Table 1. Then the two groups of signals are subjected to dynamic range expansion through an amplitude control circuit and spurious and harmonic filtering through an eight-way switch filter group. After the signals are combined, a 0.2-2GHz intermediate frequency signal and a 0.2-2GHz intermediate frequency signal for self-checking are finally output.

[0044] Figure 2For the variable frequency circuit 1, the radio frequency input signal is adjusted in power by a fixed first attenuator 10 and then enters a mixer 11 radio frequency port. The local oscillator signal is improved to a certain power level by a first amplifier 14, then filtered to remove the harmonics of the local oscillator signal by a low pass filter, i.e. a second filter 15, then adjusted in power by a third attenuator 16 and matched between link stages, and at the same time drives the mixer 11 to work, then obtains an intermediate frequency output signal which enters a second attenuator 12, and finally enters the subsequent amplitude control circuit 2 after being filtered by an LC low pass filter, i.e. a first filter 13, to remove the image frequency signal.

[0045] Figure 3 For the amplitude control circuit 2, its main function is to adjust the power of the intermediate frequency signal obtained by the variable frequency circuit part to ensure the signal harmonic performance. The circuit mainly uses high linearity amplifiers, large dynamic low step digital attenuators and fixed attenuators to adjust the amplitude of the link signal and improve the performance. The intermediate frequency signal obtained by the variable frequency is first passed through a second amplifier 20, then through a first digital attenuator 21 with a step of 0.25dB and a total attenuation of 15.5dB, then through a fourth attenuator 22 to improve the signal harmonic characteristics of the link, then through a third amplifier 23 to amplify the signal, then through a second digital attenuator 24 with a step of 0.5dB and a total attenuation of 31.5dB, then through a fifth attenuator 25 to improve the harmonic characteristics of the link signal, then through a fourth amplifier 26 to amplify the signal, then through a third digital attenuator 27 with a step of 0.5dB and an attenuation of 31.5dB, then through a fifth amplifier 28 to reach the maximum power value, and then through a first equalizer 29 for amplitude correction before entering the next stage circuit.

[0046] Figure 4 For the switch filter bank 3, the main function of this part of the circuit is to filter out harmonics and spurs from the signal obtained by the variable frequency into eight paths, while performing amplitude correction. First, the amplitude-corrected signal is divided into eight paths by a first single-pole eight-throw switch, then a single-pole single-throw switch is added to each path to increase the isolation between channels, then the signal is filtered by the third filter 32 corresponding to the branch, then the amplitude of the signal in the branch is corrected by the second equalizer 33, and finally the signals in the eight paths are combined into one path by the second single-pole eight-throw switch 34. The third equalizer 35 on the output link performs amplitude correction again, and then the signal is divided into two paths by the coupler 36, one of which is a 0.2-2GHz signal directly output, and the other is a self-checking signal to detect whether the circuit functions normally. The specific frequency allocation of the eight filters is shown in Table 1.

[0047] The main technical indicators of the entire wideband variable frequency assembly are:

[0048] Radio frequency input signal: 3-4GHz;

[0049] Signal input power: -8 ± 1dBm;

[0050] Local oscillator input signal: 4 / 5GHz;

[0051] Local oscillator signal power: 0 ± 3dBm;

[0052] Output signal power: 9-11dBm,

[0053] Self-test path coupling degree: 10dB;

[0054] Receive gain in-band flatness: ≤ ± 1.5dB;

[0055] Output signal harmonic: 0.2-0.38GHz ≤ -48dBc;

[0056] 0.38-2GHz ≤ -50dBc;

[0057] Output signal spurious: ≥ 50dBc;

[0058] Amplitude control range: ≥ 60dB;

[0059] Internal attenuator step (dB): 0.25dB;

[0060] The multi-range wideband frequency conversion assembly of the embodiment is composed of two input ports and two output ports. The two input ports are a radio frequency input port and a local oscillator port respectively. The two output ports are an intermediate frequency output port and a self-test port respectively. A wideband coupler divides the output signal into two paths. The signal power of the straight-through path is directly output. The power of the other path is output after passing through a 10dB coupler as a self-test path output. The working frequency covers 0.2-2GHz, and the coverage frequency range reaches ten times.

[0061] The multi-range wideband frequency conversion assembly of the embodiment. The radio frequency signal obtained through frequency conversion is amplified in power through a four-stage amplifier and is controlled in amplitude through a three-stage digital attenuator. The harmonic performance before entering the switch filter group can be ensured to be in the linear dynamic range, and the step is only 0.25dB, and the total attenuation range reaches 60dB.

[0062] The multi-range wideband frequency conversion assembly of the embodiment. According to the frequency band width of the final output signal frequency, and considering the spurious and harmonic requirements, the output signal is subdivided into eight frequency bands. The specific frequency band division is shown in Table 1. A filter is arranged for each frequency band to filter out harmonics and spurious. The harmonic suppression of the selected switch harmonic performance under the condition of high-power input can reach more than 48dBc. The signal power after the filter group can reach more than 10dBm, while meeting the harmonic of more than 48dBc and the spurious of more than 50dBc.

[0063] The multi-bandwidth variable frequency assembly of the embodiment can correct the power of the whole output signal through the first equalizer in the signal control part circuit according to the band width and power flatness of the final output signal frequency, and can correct the power of each radio frequency signal in the eight-way filter group through the equalizers 1-8, and finally can correct the overall amplitude of the full-band signal after the eight-way filter group, so that the flatness of ±1dB can be finally realized.

Claims

1. A multi-octave wideband frequency conversion assembly, comprising: It comprises a frequency conversion circuit (1), an amplitude control circuit (2), and a switch filter group (3), wherein: The frequency conversion circuit (1) expands the frequency of an input radio frequency signal to an intermediate frequency signal through two local oscillator frequency points and outputs the intermediate frequency signal to the amplitude control circuit (2); The amplitude control circuit (2) adjusts the amplitude of the intermediate frequency signal output by the frequency conversion circuit (1); The switch filter group (3) filters out harmonics and stray signals through a multi-path filter group and performs amplitude correction to obtain a multi-octave intermediate frequency output signal; The frequency conversion circuit (1) is specifically as follows: An input radio frequency signal is input to the radio frequency port of a mixer (11) after being adjusted in power by a first attenuator (10); a local oscillator signal is raised to a set power level by a first amplifier (14), filtered to remove harmonics of the local oscillator signal by a second filter (15), adjusted in power and matched between link levels by a third attenuator (16), and then input to the local oscillator input end of the mixer (11); the mixer (11) outputs the obtained intermediate frequency signal to a second attenuator (12), and the final intermediate frequency signal is obtained after the mirror frequency signal is filtered out by a first filter (13) and output to the amplitude control circuit (2); The amplitude control circuit (2) comprises a second amplifier (20), a first digital attenuator (21), a fourth attenuator (22), a third amplifier (23), a second digital attenuator (24), a fifth attenuator (25), a fourth amplifier (26), a third digital attenuator (27), a fifth amplifier (28), and a first equalizer (29) connected in sequence; The intermediate frequency signal output by the frequency conversion circuit (1) is first amplified by the second amplifier (20), then adjusted in signal harmonic characteristics by the first digital attenuator (21) and the fourth attenuator (22), then amplified by the third amplifier (23) and the fourth amplifier (26), then adjusted in signal harmonic characteristics by the second digital attenuator (24) and the fifth attenuator (25), and finally output to the switch filter group (3) after the power value reaches the maximum after being amplified by the fifth amplifier (28) and the amplitude is corrected by the first equalizer (29); The switch filter group (3) comprises a first single-pole N-throw switch (30), a single-pole single-throw switch (31), a third filter (32), a second equalizer (33), a second single-pole N-throw switch (34), a third equalizer (35), and a coupler (36), wherein N is a natural number greater than 2. The amplitude control circuit (2) outputs the amplitude corrected signal, which is divided into N paths through the first single-throw N-pole switch (30); each path includes a group of single-throw single-pole switches (31) connected in sequence, a third filter (32), and a second equalizer (33), the single-throw single-pole switch (31) is used to increase the isolation between channels, and the second equalizer (33) is used to correct the amplitude of the split radio frequency signal; the N paths of the amplitude corrected signal are combined into a full band signal through the second single-throw N-pole switch (34), the third equalizer (35) performs overall amplitude correction on the full band signal and outputs it to the coupler (36), and the coupler (36) divides the received signal into two paths, one of which is directly output, and the other is used as a self-test signal.

2. The multi-octave wideband frequency conversion assembly of claim 1, wherein, The radio frequency signal input into the frequency conversion circuit (1) is 3-4GHz, and the corresponding radio frequency signal 3.1-3.8GHz is converted to 0.2-0.9GHz using a 4GHz local oscillator signal, then the local oscillator signal is switched to 5GHz, and then 3.1-4.1GHz is converted to 0.9-2GHz; the switch filter group (3) filters out harmonics and spurs of the output intermediate frequency signal with a span of ten times the frequency, including one 0.2-2GHz intermediate frequency signal and one 0.2-2GHz intermediate frequency signal for self-test.

3. The multi-octave wideband frequency conversion assembly of claim 2, wherein, The corresponding radio frequency signal 3.1-3.8GHz is converted to 0.2-0.9GHz using a 4GHz local oscillator signal, then the local oscillator signal is switched to 5GHz, and then 3.1-4.1GHz is converted to 0.9-2GHz, and the specific conversion relationship is shown in Table 1: Table 1 。 4. The multi-octave wideband frequency conversion assembly of claim 1, wherein, The step of the first digital attenuator (21) is 0.25dB, and the total attenuation is 15.5dB; the step of the second digital attenuator (24) is 0.5dB, and the total attenuation is 31.5dB; the step of the third digital attenuator (27) is 0.5dB, and the attenuation is 31.5dB.

5. The multi-octave wideband frequency conversion assembly of claim 1, wherein, The value of N is 8, and the first single-throw N-pole switch (30) and the second single-throw N-pole switch (34) are both single-throw eight-pole switches.

6. The multi-octave wideband frequency conversion assembly of claim 1, wherein, The coupler (36) is a 10dB coupler.

7. The multi-octave wideband frequency conversion assembly of claim 3, wherein, The radio frequency signal input power of the entire wideband frequency conversion assembly is -8±1dBm; the local oscillator signal power is 0±3dBm; the output signal power is 9-11dBm; the receive gain in-band flatness is ≤±1.5dB; the output signal harmonic is 0.2-0.38GHz ≤-48dBc; 0.38-2GHz ≤-50dBc; the output signal spur is ≥50dBc; and the amplitude control range is ≥60dB.

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