Topological structure of multi-frequency-point adjustable notch equalizer with filtering characteristic

Abstract

The invention relates to the field of microwave and millimeter wave circuits, and provides a topological structure of a multi-frequency-point adjustable notch equalizer with a filtering characteristic, which comprises a plurality of adjustable notch equalization units connected in parallel, each adjustable notch equalization unit comprises a first resistor, a first inductor and a first adjustable capacitor which are connected in series; and a converter is connected between every two adjustable trapped wave equalization units. According to the invention, a plurality of independent and adjustable trapped wave equalization frequency points can be realized, and a good standing wave is ensured at the same time. On the basis, the topological structure has a filtering characteristic with adjustable passband frequency.

Description

Technical Field

[0001] This invention relates to the field of microwave and millimeter-wave circuits, and more specifically, to a topology of a multi-frequency adjustable notch equalizer with filtering characteristics. Background Technology

[0002] Current research on equalizers mainly falls into two categories: linear positive slope equalizers and notch equalizers. Notch equalizers typically employ methods such as... Figure 1 The RLC series resonant unit shown is used to implement this. This type of structure, by connecting several RLC series resonant units in parallel to ground, can achieve the design of a multi-frequency notch equalizer. If the capacitor in the RLC series resonant unit is replaced with a variable capacitor, a multi-frequency adjustable notch equalizer can be designed. However, this design has the following drawbacks in practical applications: 1. Since the RLC series resonant unit is essentially a notch filter circuit, if several RLC series resonant units are used directly, the standing wave ratio of the entire multi-frequency notch filter equalizer will be correspondingly poor.

[0003] 2. The device has a single function, which does not conform to the current trend of miniaturization in multi-functional integrated designs. Summary of the Invention

[0004] To address the problems existing in the design of multi-frequency notch equalizers based on RLC series resonant units, this invention aims to provide a topology of a multi-frequency adjustable notch equalizer with filtering characteristics, so as to ensure good standing wave ratio while achieving multiple independently adjustable notch equalization frequencies. On this basis, the topology has filtering characteristics with adjustable passband frequency.

[0005] This invention provides a topology for a multi-frequency adjustable notch equalizer with filtering characteristics, comprising: A plurality of adjustable notch equalizer units connected in parallel; each of the adjustable notch equalizer units includes a first resistor, a first inductor and a first adjustable capacitor connected in series; Each of the adjustable notch equalizer units is connected to a converter.

[0006] In a preferred embodiment, the converter is a high-pass reconfigurable filter unit.

[0007] In a preferred embodiment, the converter is a low-pass reconfigurable filter unit.

[0008] In a preferred embodiment, the converter is implemented using both a high-pass reconfigurable filter unit and a low-pass reconfigurable filter unit.

[0009] In a preferred embodiment, the Qualcomm reconfigurable filter unit includes a second inductor, a second adjustable capacitor, and two second capacitors; The two second capacitors are connected in series between the adjustable notch equalizer unit; The electrical connection point between the two second capacitors is grounded via the second inductor and the second adjustable capacitor.

[0010] In a preferred embodiment, the low-pass reconfigurable filter unit includes a third adjustable capacitor and two third inductors; The two third inductors are connected in series between the adjustable notch equalizer units; The electrical connection point between the two third inductors is grounded via the third adjustable capacitor.

[0011] In a preferred embodiment, the resonant frequency of the adjustable notch equalization unit is determined by the capacitance of the first adjustable capacitor and the inductance of the first inductor. The notch equalization frequency is changed by adjusting the capacitance of the first adjustable capacitor. The notch depth is determined by the first resistor. The smaller the resistance of the first resistor, the greater the notch depth.

[0012] In a preferred embodiment, the resonant frequency is calculated using the following formula:

[0013] in, The resonant frequency, L This is the inductance value of the first inductor. C This is the capacitance value of the first adjustable capacitor.

[0014] In summary, this invention achieves multiple independently adjustable notch equalization frequencies while maintaining good standing wave ratios. Furthermore, this topology possesses passband frequency-adjustable filtering characteristics. Specifically, its beneficial effects are: 1. The present invention, through a multi-frequency adjustable notch equalizer with topology design, can improve the in-band ripple caused by various components and impedance mismatch in the system to a certain extent.

[0015] 2. This invention is achieved through... N Several parallel RLC resonant stubs are used to achieve several notch filter equalization frequencies, and the independent adjustability of several notch filter equalization frequencies is achieved through a variable capacitor.

[0016] 3. This invention embeds a reconfigurable high-pass / low-pass unit as a converter into the notch equalizer link, thereby achieving the fusion of filtering characteristics, notch equalization characteristics, and reconfigurable characteristics without increasing the volume. Attached Figure Description

[0017] Figure 1 This is a structural diagram of a notch equalizer implemented using a common RLC series resonant unit.

[0018] Figure 2The diagram shows a third-order topology of a multi-frequency adjustable notch equalizer with filtering characteristics, provided in an embodiment of the present invention.

[0019] Figure 3a This is a structural diagram of a high-pass reconfigurable filter unit that can be used in a converter in an embodiment of the present invention.

[0020] Figure 3b This is a structural diagram of a low-pass reconfigurable filter unit that can be used in a converter in an embodiment of the present invention.

[0021] Figure 4 This invention provides a multi-frequency adjustable notch equalizer with filtering characteristics. N Topological structure diagram.

[0022] Figure 5 This is a topology diagram of a multi-frequency adjustable notch equalizer with filtering characteristics that uses a low-pass reconfigurable filter unit in one example of the present invention.

[0023] Figure 6 for Figure 5 Simulation curves of the transmission response of a medium-adjustable notch equalizer at different frequency points.

[0024] Figure 7 for Figure 5 Simulation curve of echo response of adjustable notch equalizer.

[0025] Figure 8 for Figure 5 Simulation curves of the transmission response at dual equalization frequencies of a medium-adjustable notch equalizer.

[0026] Figure 9 for Figure 5 Simulation curves of the transmission response of a reconfigurable low-pass filter with adjustable notch equalizer. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] Example The in-band ripple of the intermediate frequency (IF) directly affects the dynamic range of the entire system. It mainly comes from the in-band ripple of the RF front-end before frequency conversion and the in-band ripple of the IF itself, such as that generated by the IF filter. As system functions become increasingly complex, it is very difficult to improve the in-band ripple of the entire link by constraining the in-band ripple of each device and chip, and it will consume a lot of debugging resources. At the same time, as the integration of electronic systems is becoming higher and higher, the design approach of integrating multiple functions into a single device is more important.

[0030] In view of this, such as Figure 2 As shown, this embodiment of the invention provides a topology for a multi-frequency adjustable notch equalizer with filtering characteristics. The notch equalizer designed according to this structure generates M (0≤M≤N) notch equalization frequencies based on the number of applied bias voltages. The frequencies of these notch equalization frequencies can be tuned by adjusting the capacitance of a variable capacitor. In conventional notch equalizer design, to improve the overall standing wave ratio (SWR) of the device, an inverter needs to be added between each notch equalization branch. This inverter can usually be replaced by a transmission line or an RC network. However, in this embodiment of the invention, a high-pass reconfigurable filter unit or a low-pass reconfigurable filter unit is used to implement the inverter function. This achieves the filtering characteristics of the notch equalizer while ensuring the SWR performance of the notch equalizer. Furthermore, the filtering characteristics are adjustable, and the high-pass or low-pass reconfigurable filter unit can be of any order.

[0031] Figure 2 The resonant circuit consisting of the first resistor, the first inductor, and the first adjustable capacitor in the parallel RLC resonant stub constitutes an adjustable notch equalizer unit. The resonant frequency of this adjustable notch equalizer unit is determined by the capacitance of the first adjustable capacitor and the inductance of the first inductor, and its resonant frequency is... ,in, The resonant frequency, L This is the inductance value of the first inductor. C The capacitance value of the first adjustable capacitor is used to change the notch equalization frequency by adjusting the capacitance value of the first adjustable capacitor. The notch depth is determined by the first resistor; the smaller the resistance value of the first resistor, the greater the notch depth.

[0032] Figure 3a This is a high-pass reconfigurable filter unit that can be used in a converter. The high-pass reconfigurable filter unit includes a second inductor, a second adjustable capacitor, and two second capacitors. The two second capacitors are connected in series between the adjustable notch equalizer unit; The electrical connection point between the two second capacitors is grounded via the second inductor and the second adjustable capacitor.

[0033] Figure 3bThis is a low-pass reconfigurable filter unit that can be used in a converter. The low-pass reconfigurable filter unit includes a third adjustable capacitor and two third inductors; The two third inductors are connected in series between the adjustable notch equalizer units; The electrical connection point between the two third inductors is grounded via the third adjustable capacitor.

[0034] Will Figure 3a , Figure 3b The high-pass reconfigurable filter unit or the low-pass reconfigurable filter unit is embedded in each adjustable notch equalizer unit to realize the reconfigurable filtering characteristics of the notch equalizer. One or both of the high-pass reconfigurable filter unit and the low-pass reconfigurable filter unit can be used to realize the reconfigurable bandpass filtering characteristics.

[0035] This invention integrates multiple functional characteristics into a single device by embedding a reconfigurable filter unit into the design of an adjustable notch equalizer, while ensuring technical specifications.

[0036] The topology proposed in this invention does not limit the implementation methods and processes of components such as R, L, and C. It can be implemented in microwave frequency bands using methods such as microstrip lines, striplines, suspension lines, lumped elements, cavities, etc., and processes such as thin films, thick films, LTCC, three-dimensional stacking, etc.

[0037] like Figure 4 As shown, N A step-adjustable notch equalizer can directly convert... Figure 2 The given topology cascade extension of the third-order adjustable notch equalizer is sufficient.

[0038] The following example uses a topology where a low-pass reconfigurable filter unit is embedded with an adjustable notch equalizer: Figure 5 The topology of a multi-frequency adjustable notch equalizer with filtering characteristics using a low-pass reconfigurable filter unit is shown.

[0039] Figure 6 Showing Figure 5 Simulation curves of the transmission response of the adjustable notch equalizer at different frequency points show that the notch frequency point of the adjustable notch equalizer can be tuned with external control in the range of 1.3GHz-2.3GHz.

[0040] Figure 7 Showing Figure 5 The simulation curve of the return response of the adjustable notch equalizer shows that the adjustable notch equalizer has good return loss characteristics.

[0041] Figure 8 Showing Figure 5The simulation curves of the dual-equalization frequency points transmission response of the adjustable notch equalizer show that the number of notch equalization frequencies can be flexibly configured according to changes in external control.

[0042] Figure 9 Showing Figure 5 The simulation curve of the reconfigurable low-pass transmission response of the adjustable notch equalizer shows that the low-pass filtering effect of the adjustable notch equalizer outside the passband of 1.3GHz-2.3GHz demonstrates its filtering characteristics.

[0043] From the above, we can conclude that: 1. The present invention, through a multi-frequency adjustable notch equalizer with topology design, can improve the in-band ripple caused by various components and impedance mismatch in the system to a certain extent.

[0044] 2. This invention is achieved through... N Several parallel RLC resonant stubs are used to achieve several notch filter equalization frequencies, and the independent adjustability of several notch filter equalization frequencies is achieved through a variable capacitor.

[0045] 3. This invention embeds a reconfigurable high-pass / low-pass unit as a converter into the notch equalizer link, thereby achieving the fusion of filtering characteristics, notch equalization characteristics, and reconfigurable characteristics without increasing the volume.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A topology of a multi-frequency adjustable notch equalizer with filtering characteristics, characterized in that, include: A plurality of adjustable notch equalizer units connected in parallel; each of the adjustable notch equalizer units includes a first resistor, a first inductor and a first adjustable capacitor connected in series; Each of the adjustable notch equalizer units is connected to a converter.

2. The topology of the multi-frequency adjustable notch equalizer with filtering characteristics according to claim 1, characterized in that, The converter is a high-pass reconfigurable filter unit.

3. The topology of the multi-frequency adjustable notch equalizer with filtering characteristics according to claim 1, characterized in that, The converter is a low-pass reconfigurable filter unit.

4. The topology of the multi-frequency adjustable notch equalizer with filtering characteristics according to claim 1, characterized in that, The converter is implemented using both a high-pass reconfigurable filter unit and a low-pass reconfigurable filter unit.

5. The topology of the multi-frequency adjustable notch equalizer with filtering characteristics according to claim 2 or 4, characterized in that, The high-pass reconfigurable filter unit includes a second inductor, a second adjustable capacitor, and two second capacitors; The two second capacitors are connected in series between the adjustable notch equalizer unit; The electrical connection point between the two second capacitors is grounded via the second inductor and the second adjustable capacitor.

6. The topology of the multi-frequency adjustable notch equalizer with filtering characteristics according to claim 3 or 4, characterized in that, The low-pass reconfigurable filter unit includes a third adjustable capacitor and two third inductors; The two third inductors are connected in series between the adjustable notch equalizer unit; The electrical connection point between the two third inductors is grounded via the third adjustable capacitor.

7. The topology of the multi-frequency adjustable notch equalizer with filtering characteristics according to claim 1, characterized in that, The resonant frequency of the adjustable notch equalization unit is determined by the capacitance of the first adjustable capacitor and the inductance of the first inductor. The notch equalization frequency is changed by adjusting the capacitance of the first adjustable capacitor. The notch depth is determined by the first resistor. The smaller the resistance of the first resistor, the greater the notch depth.

8. The topology of the multi-frequency adjustable notch equalizer with filtering characteristics according to claim 7, characterized in that, The formula for calculating the resonant frequency is as follows: in, The resonant frequency, L This is the inductance value of the first inductor. C This is the capacitance value of the first adjustable capacitor.

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