Symmetrical layout structure of I-type and II-type RC multi-phase filters
The symmetrical layout structure design ensures that the connection line lengths of the resistor and capacitor components in the RC multi-phase filter are consistent, solving the problem of impaired orthogonality in traditional designs, improving matching accuracy and electrical characteristics, and making it suitable for multi-stage cascade applications.
Patent Information
- Application Number
- CN202510804815.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-17
- Publication Date
- 2025-09-12
AI Technical Summary
The layout of resistors and capacitors in traditional RC polyphase filters results in inconsistent metal wire lengths, affecting the orthogonality of the output signals. This makes it difficult to ensure the matching and consistency of resistors and capacitors, especially in high-frequency and multi-stage cascade applications.
A symmetrical layout structure is adopted, so that the resistance elements and the capacitance elements are alternately connected in series to form a closed loop, and are arranged longitudinally symmetrically about the longitudinal axis. The center spacing of adjacent elements is the same, the length of the connecting wires is consistent, the resistors and capacitors are placed in different areas, and the length of the connecting wires of the in-phase and orthogonal component signals is kept the same in the multi-stage filter cascade.
It effectively avoids the problem of output signal orthogonality loss caused by inconsistent connecting wire lengths, improves device matching accuracy and electrical characteristic balance, and is suitable for multi-stage cascade applications.
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Figure CN120633561A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of integrated circuit design, and in particular to a symmetrical layout structure of type I and type II RC polyphase filters. Background Art
[0002] RC polyphase filters are widely used in systems such as communications and radar due to their simple circuit structure, high robustness, and low cost. Their primary applications include, but are not limited to, generating orthogonal signals and achieving image rejection. By inputting differential signals to an RC polyphase filter, orthogonal differential output signals are generated, consisting of an in-phase component (in-phase) and a quadrature component (quadrature).
[0003] like Figure 1 and Figure 2 As shown in the figure, in the layout design of traditional Type I and Type II RC polyphase filters, the layout of resistors and capacitors often leads to inconsistent metal connecting wire lengths, which in turn impairs the orthogonality of the output signals. This problem becomes increasingly severe with increasing frequency, especially in the millimeter wave band. In addition, due to the staggered placement of resistors and capacitors in traditional RC polyphase filters, the matching and consistency of these two passive components are difficult to ensure, especially in multi-stage RC polyphase filter cascade applications. Therefore, an optimized layout structure is needed to address these issues. Summary of the Invention
[0004] The object of the present invention is to provide a symmetrical layout structure that is applicable to both Type I and Type II RC polyphase filters.
[0005] The technical solution of the present invention is: a symmetrical layout structure of type I and type II RC polyphase filters, the layout structure comprising: a first resistor R1; a second resistor R2; a third resistor R3; a fourth resistor R4 and a first capacitor C1; a second capacitor C2; a third capacitor C3; and a fourth capacitor C4, wherein the resistors and capacitors are alternately connected in series to form a closed loop, i.e., the first resistor R1 is connected to the first capacitor C1, the first capacitor C1 is connected to the second resistor R2, the second resistor R2 is connected to the second capacitor C2, the second capacitor C2 is connected to the third resistor R3, the third resistor R3 is connected to the fourth capacitor C4, and the fourth capacitor C4 is connected to the first resistor R1. To maintain the connection relationship, the resistor elements are arranged longitudinally symmetrically about the vertical axis, with the center spacing between adjacent resistor elements being the same, and the capacitor elements are arranged longitudinally symmetrically about the vertical axis, with the center spacing between adjacent capacitor elements being the same, and the center spacing between adjacent resistor elements and the center spacing between adjacent capacitor elements are the same. The resistor columns and capacitor columns are arranged transversely symmetrically about the transverse axis.
[0006] Furthermore, the connecting line between the first resistor R1 and the first capacitor C1, the connecting line between the third resistor R3 and the third capacitor C3, the connecting line between the first capacitor C1 and the second resistor R2, the connecting line between the second capacitor C2 and the third resistor R3, the connecting line between the first resistor R1 and the fourth capacitor C4, the connecting line between the fourth resistor R4 and the third capacitor C3, the connecting line between the fourth resistor R4 and the fourth capacitor C4, and the connecting line between the second resistor R2 and the second capacitor C2 are all the same length.
[0007] Furthermore, in the I-type RC multinomial filter, the connection port between the first resistor R1 and the first capacitor C1 and the connection port between the third resistor R3 and the third capacitor C3 are differential signal input ports, the connection port between the fourth capacitor C4 and the first resistor R1 and the connection port between the second capacitor C2 and the third resistor R3 are in-phase component differential signal output ports, and the connection port between the third capacitor C3 and the fourth resistor R4 and the connection port between the first capacitor C1 and the second resistor R2 are orthogonal component differential signal output ports.
[0008] Furthermore, in the type II RC multinomial filter, the connection port of the first resistor R1 and the first capacitor C1 and the connection port of the second resistor R2 and the second capacitor C2 are connected and merged into one port, the connection port of the third resistor R3 and the third capacitor C3 and the connection port of the fourth resistor and the fourth capacitor are connected and merged into one port, the aforementioned two merged ports are differential signal input ports, the connection port of the fourth capacitor C4 and the first resistor R1 and the connection port of the second capacitor C2 and the third resistor R3 are in-phase component differential signal output ports, and the connection port of the third capacitor C3 and the fourth resistor R4 and the connection port of the first capacitor C1 and the second resistor R2 are orthogonal component differential signal output ports.
[0009] Furthermore, the resistor elements and capacitor elements are placed in different regions in the layout, with the dummy cells of the resistor elements being filled in the resistor region and the dummy cells of the capacitor elements being filled in the capacitor region.
[0010] Furthermore, for a cascade of multiple RC polyphase filters, the output signal of the preceding RC polyphase filter (hereinafter referred to as the preceding stage) serves as the input signal of the succeeding RC polyphase filter (hereinafter referred to as the succeeding stage), and the preceding and succeeding stages are symmetrical about the horizontal axis. The in-phase component differential signal output by the preceding stage is connected to the connection port between the first resistor R1 and the first capacitor C1, and the connection port between the third resistor R3 and the third capacitor C3, of the succeeding stage. The quadrature component differential signal output by the preceding stage is connected to the connection port between the fourth resistor R4 and the fourth capacitor C4, and the connection port between the second resistor R2 and the second capacitor C2, of the succeeding stage. For each pair of poles, the connection port between the fourth capacitor C4 and the first resistor R1, and the connection port between the second capacitor C2 and the third resistor R3, of the succeeding stage serve as the output port for the in-phase component differential signal. The connection port between the third capacitor C3 and the fourth resistor R4, and the connection port between the first capacitor C1 and the second resistor R2, serve as the output port for the quadrature component differential signal. The connection wire lengths for the in-phase component differential signal and the quadrature component differential signal are the same.
[0011] Beneficial effects of the present invention: The present invention ensures that the length of the metal connecting wires between the resistor elements and the capacitor elements in the RC multi-phase filter is consistent through a specific arrangement and connection method, thereby effectively avoiding the problem of impaired orthogonality of the output signal due to inconsistent lengths of the connecting wires. The design of placing the resistor elements and the capacitor elements in separate areas is conducive to filling virtual units in their respective areas, which not only improves the matching accuracy of the device, but also balances the electrical characteristics of the layout. Furthermore, in the case of a multi-stage RC multi-phase filter cascade, the present invention can still ensure that the length of the connecting wires of the in-phase component signal and the orthogonal component signal between each stage is the same, and has good scalability and compatibility. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a schematic diagram of the layout structure of a traditional type I RC polyphase filter.
[0013] Figure 2 This is a schematic diagram of the layout structure of a traditional Type II RC polyphase filter.
[0014] Figure 3 1 is a schematic diagram of the layout structure of a two-stage I-type RC polyphase filter according to Example 1 of the present invention.
[0015] Figure 4 4 is a layout of a two-stage I-type RC polyphase filter according to embodiment 1 of the present invention.
[0016] Figure 5 These are simulation results of the two-stage I-type RC polyphase filter according to Example 1 of the present invention and a traditional two-stage I-type RC polyphase filter.
[0017] Figure 6 1 is a schematic diagram of the layout structure of a two-stage type II RC polyphase filter according to embodiment 2 of the present invention.
[0018] Figure 7 4 is a layout of a two-stage type II RC polyphase filter according to embodiment 2 of the present invention.
[0019] Figure 8 These are simulation results of the two-stage Type II RC polyphase filter according to Example 2 of the present invention and a traditional two-stage Type II RC polyphase filter. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Any changes made on the basis of the technical solutions in accordance with the technical ideas proposed by the present invention fall within the scope of protection of the claims of the present invention. Unless otherwise expressly indicated, throughout the specification and claims, the term "including" or its variations such as "comprising" or "including" will be understood to include the stated elements or components, without excluding other elements or other components.
[0021] Example 1
[0022] This embodiment provides a two-stage I-type RC polyphase filter layout structure, including the first stage RC polyphase filter filter and the second-stage RC multi-stage filter (hereinafter referred to as the first stage and the second stage). Figure 3 This is a schematic diagram of the layout structure of this embodiment (the schematic diagram does not include virtual units), including: the first resistor of the first level ; Second resistor ; The third resistor ; The fourth resistor and the first capacitor ; Second capacitor ; The third capacitor ; The fourth capacitor The first-stage resistance elements and capacitance elements are connected in series alternately to form a closed loop, that is, the first resistance Connect the first capacitor , the first capacitor Connect the second resistor , the second resistor Connect the second capacitor , the second capacitor Connect the third resistor , the third resistor Connect the fourth capacitor , the fourth capacitor Connect the first resistor Maintaining the connection relationship of the first level, the first level resistance element is about the vertical axis Symmetrical longitudinal arrangement, the center spacing between adjacent resistor elements is the same, the first-level capacitor element is about the longitudinal axis Symmetrically arranged longitudinally, the center spacing between adjacent capacitor elements is the same and is recorded as , and the center distance between adjacent resistor elements and the center distance between adjacent capacitor elements are the same and equal to .
[0023] Specifically, the first resistor With the first capacitor The connecting wire and the third resistor With the third capacitor The connecting wire of the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connecting wire of the first resistor With the fourth capacitor The connecting wire, the fourth resistor With the third capacitor The connecting wire, the fourth resistor With the fourth capacitor Connecting wire, and second resistor With the second capacitor The lengths of the connecting wires are the same, denoted as .
[0024] Specifically, the first resistor With the first capacitor The connection port and the third resistor With the third capacitor The connection port is a differential signal input port. The fourth capacitor With the first resistor The connection port and the second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor With the fourth resistor The connection port and the first capacitor With the second resistor The connection port is the orthogonal component differential signal output port.
[0025] Second level first resistor , the second resistor , the third resistor , the fourth resistor and the first capacitor , the second capacitor , the third capacitor , the fourth capacitor The first-stage resistance elements and capacitance elements are connected in series alternately to form a closed loop, that is, the first resistance Connect the first capacitor , the first capacitor Connect the second resistor , the second resistor Connect the second capacitor , the second capacitor Connect the third resistor , the third resistor Connect the fourth capacitor , the fourth capacitor Connect the first resistor Maintaining the connection relationship of the second level, the second level resistance element is about the vertical axis Symmetrical longitudinal arrangement, the center spacing between adjacent resistor elements is the same, and the second-level capacitor element is about the longitudinal axis. Symmetrical longitudinal arrangement, the center spacing between adjacent capacitor elements is the same and equal to , and the center distance between adjacent resistor elements and the center distance between adjacent capacitor elements are the same and equal to .
[0026] Specifically, the first resistor With the first capacitor The connecting wire and the third resistor With the third capacitor The connecting wire of the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connecting wire of the first resistor With the fourth capacitor The connecting wire, the fourth resistor With the third capacitor The connecting wire, the fourth resistor With the fourth capacitor Connecting wire, and second resistor With the second capacitor The lengths of the connecting wires are the same, denoted as .
[0027] Specifically, the first resistor With the first capacitor The connection port and the third resistor With the third capacitor The connection port is a differential signal input port. The fourth capacitor With the first resistor The connection port and the second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor With the fourth resistor The connection port and the first capacitor With the second resistor The connection port is the orthogonal component differential signal output port.
[0028] The aforementioned two-stage RC polyphase filter is about the horizontal axis. They are arranged symmetrically and cascaded, with the output signal of the first stage serving as the input signal of the second stage.
[0029] Specifically, the in-phase component differential signal output by the first stage is connected to the in-phase component input differential port of the second stage, and the quadrature component differential signal output by the first stage is connected to the quadrature component input differential port of the second stage. The length of the connection line of the in-phase component differential signal is the same as the length of the connection line of the quadrature component differential signal, which is recorded as .
[0030] Figure 4 For the layout implementation of this embodiment, a 40nm CMOS process is used with an operating frequency of 77 GHz. Poly resistors are selected as resistors, and MOM capacitors are selected as capacitors. Different layers of metal are used for crossover at the intersection of the connecting lines, and the metal thickness is kept consistent. The vias are not shown. The dummy cells (Dummy) of the resistor elements in each level are filled between the resistor elements and have the same size as the resistor elements in that level. The dummy cells (Dummy) of the capacitor elements in each level are filled at both ends of the capacitor column and have the same size as the resistor elements in that level. This layout method arranges the poly and metal in different areas, effectively improving the matching accuracy of the device and balancing the electrical characteristics of the layout.
[0031] Figure 5 The simulation results of the two-stage I-type RC polyphase filter of this embodiment are compared with those of a conventional two-stage I-type RC polyphase filter. Comparing the layout implementation of this embodiment with the simulation results shows that the I-type RC polyphase filter using the layout structure of the present invention can effectively maintain orthogonality of the output signals over a wide bandwidth and is suitable for multi-stage cascade applications.
[0032] Example 2
[0033] This embodiment provides a layout structure of a two-stage Type II RC polyphase filter, including a first-stage RC polyphase filter and a second-stage RC polyphase filter (hereinafter referred to as the first stage and the second stage). Figure 6 This is a schematic diagram of the layout structure of this embodiment (the schematic diagram does not include virtual units), including: the first resistor of the first level , the second resistor , the third resistor , the fourth resistor and the first capacitor , the second capacitor , the third capacitor , the fourth capacitor The first-stage resistance elements and capacitance elements are connected in series alternately to form a closed loop, that is, the first resistance Connect the first capacitor , the first capacitor Connect the second resistor , the second resistor Connect the second capacitor , the second capacitor Connect the third resistor , the third resistor Connect the fourth capacitor , the fourth capacitor Connect the first resistor Maintaining the connection relationship of the first level, the first level resistance element is about the vertical axis Symmetrical longitudinal arrangement, the center spacing between adjacent resistor elements is the same, the first-level capacitor element is about the longitudinal axis Symmetrically arranged longitudinally, the center spacing between adjacent capacitor elements is the same and is recorded as , and the center distance between adjacent resistor elements and the center distance between adjacent capacitor elements are the same and equal to .
[0034] Specifically, the first resistor With the first capacitor The connecting wire and the third resistor With the third capacitor The connecting wire of the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connecting wire of the first resistor With the fourth capacitor The connecting wire, the fourth resistor With the third capacitor The connecting wire, the fourth resistor With the fourth capacitor Connecting wire, and second resistor With the second capacitor The lengths of the connecting wires are the same, denoted as .
[0035] Specifically, the first resistor With the first capacitor The connection port and the second resistor With the second capacitor The connection ports are combined into one port, and the third resistor With the third capacitor The connection port and the fourth resistor and the fourth capacitor The connection ports of are combined into one port, and the two combined ports are differential signal input ports. With the first resistor The connection port and the second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor With the fourth resistor The connection port and the first capacitor With the second resistor The connection port is the orthogonal component differential signal output port.
[0036] Second level first resistor , the second resistor , the third resistor , the fourth resistor and the first capacitor , the second capacitor , the third capacitor , the fourth capacitor The first-stage resistance elements and capacitance elements are connected in series alternately to form a closed loop, that is, the first resistance Connect the first capacitor , the first capacitor Connect the second resistor , the second resistor Connect the second capacitor , the second capacitor Connect the third resistor , the third resistor Connect the fourth capacitor , the fourth capacitor Connect the first resistor Maintaining the connection relationship of the second level, the second level resistance element is about the vertical axis Symmetrical longitudinal arrangement, the center spacing between adjacent resistor elements is the same, and the second-level capacitor element is about the longitudinal axis. Symmetrical longitudinal arrangement, the center spacing between adjacent capacitor elements is the same and equal to , and the center distance between adjacent resistor elements and the center distance between adjacent capacitor elements are the same and equal to .
[0037] Specifically, the first resistor With the first capacitor The connecting wire and the third resistor With the third capacitor The connecting wire of the first capacitor With the second resistor The connecting wire, the second capacitor With the third resistor The connecting wire of the first resistor With the fourth capacitor The connecting wire, the fourth resistor With the third capacitor The connecting wire, the fourth resistor With the fourth capacitor Connecting wire, and second resistor With the second capacitor The lengths of the connecting wires are the same, denoted as .
[0038] Specifically, the first resistor With the first capacitor The connection port and the third resistor With the third capacitor The connection port is a differential signal input port. The fourth capacitor With the first resistor The connection port and the second capacitor With the third resistor The connection port is the in-phase component differential signal output port, and the third capacitor With the fourth resistor The connection port and the first capacitor With the second resistor The connection port is the orthogonal component differential signal output port.
[0039] The aforementioned two-stage RC polyphase filter is about the horizontal axis. The first stage output signal is used as the second stage input signal. Specifically, the in-phase component differential signal output by the first stage is connected to the in-phase component input differential port of the second stage, and the quadrature component differential signal output by the first stage is connected to the quadrature component input differential port of the second stage. The length of the connection line of the in-phase component differential signal is the same as the length of the connection line of the quadrature component differential signal, which is recorded as .
[0040] Figure 7For the layout implementation of this embodiment, a 40nm CMOS process is used with an operating frequency of 77 GHz. Poly resistors are selected as resistors, and MOM capacitors are selected as capacitors. Different layers of metal are used for crossover at the intersection of the connecting lines, and the metal thickness is kept consistent. The vias are not shown. The dummy cells (Dummy) of the resistor elements in each level are filled between the resistor elements and have the same size as the resistor elements in that level. The dummy cells (Dummy) of the capacitor elements in each level are filled at both ends of the capacitor column and have the same size as the resistor elements in that level. This layout method arranges the poly and metal in different areas, effectively improving the matching accuracy of the device and balancing the electrical characteristics of the layout.
[0041] Figure 8 The simulation results of the two-stage Type II RC polyphase filter of this embodiment are compared with those of a conventional two-stage Type II RC polyphase filter. Comparing the layout implementation of this embodiment with the simulation results shows that the Type II RC polyphase filter using the layout structure of the present invention can effectively maintain orthogonality of the output signals over a wide bandwidth and is suitable for multi-stage cascade applications.
[0042] In summary, in combination with the various embodiments and figures, it can be seen that the symmetrical layout structure of the Type I and Type II RC polyphase filters provided in the present invention can keep the length of the connecting wires between the resistor elements and the capacitor elements consistent, thereby effectively ensuring the orthogonality of the output signals, while significantly improving the matching of the various components. Moreover, this layout structure is still applicable in the cascade application of multi-stage RC polyphase filters.
Claims
1. A symmetrical layout structure of type I and type II RC polyphase filters, characterized in that: The layout structure includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4. The resistors and capacitors are alternately connected in series to form a closed loop, that is, the first resistor R1 is connected to the first capacitor C1, the first capacitor C1 is connected to the second resistor R2, the second resistor R2 is connected to the second capacitor C2, the second capacitor C2 is connected to the third resistor R3, the third resistor R3 is connected to the fourth capacitor C4, and the fourth capacitor C4 is connected to the first resistor R1. To maintain the connection relationship, the resistor elements are arranged longitudinally symmetrically about the vertical axis, and the center spacing between adjacent resistor elements is the same. The capacitor elements are arranged longitudinally symmetrically about the vertical axis, and the center spacing between adjacent capacitor elements is the same, and the center spacing between adjacent resistor elements is the same as the center spacing between adjacent capacitor elements. The resistor columns and capacitor columns are arranged transversely symmetrically about the transverse axis.
2. The symmetrical layout structure of type I and type II RC polyphase filters according to claim 1, characterized in that: The connecting line between the first resistor R1 and the first capacitor C1, the connecting line between the third resistor R3 and the third capacitor C3, the connecting line between the first capacitor C1 and the second resistor R2, the connecting line between the second capacitor C2 and the third resistor R3, the connecting line between the first resistor R1 and the fourth capacitor C4, the connecting line between the fourth resistor R4 and the third capacitor C3, the connecting line between the fourth resistor R4 and the fourth capacitor C4, and the connecting line between the second resistor R2 and the second capacitor C2 are all the same length.
3. The symmetrical layout structure of type I and type II RC polyphase filters according to claims 1 and 2, characterized in that: In the I-type RC multinomial filter, the connection port between the first resistor R1 and the first capacitor C1 and the connection port between the third resistor R3 and the third capacitor C3 are differential signal input ports, the connection port between the fourth capacitor C4 and the first resistor R1 and the connection port between the second capacitor C2 and the third resistor R3 are in-phase component differential signal output ports, and the connection port between the third capacitor C3 and the fourth resistor R4 and the connection port between the first capacitor C1 and the second resistor R2 are orthogonal component differential signal output ports.
4. The symmetrical layout structure of type I and type II RC polyphase filters according to claims 1 and 2, characterized in that: In the Type II RC polynomial filter, the connection port between the first resistor R1 and the first capacitor C1 and the connection port between the second resistor R2 and the second capacitor C2 are combined into a single port. The connection port between the third resistor R3 and the third capacitor C3 and the connection port between the fourth resistor R4 and the fourth capacitor C4 are combined into a single port. These two combined ports serve as differential signal input ports. The connection port between the fourth capacitor C4 and the first resistor R1 and the connection port between the second capacitor C2 and the third resistor R3 serve as in-phase component differential signal output ports. The connection port between the third capacitor C3 and the fourth resistor R4 and the connection port between the first capacitor C1 and the second resistor R2 serve as quadrature component differential signal output ports.
5. The symmetrical layout structure of type I and type II RC polyphase filters according to any one of claims 1 to 4, characterized in that: The resistor elements and capacitor elements are placed in different areas in the layout, the virtual cells of the resistor elements are filled in the resistor area, and the virtual cells of the capacitor elements are filled in the capacitor area.
6. The symmetrical layout structure of type I and type II RC polyphase filters according to any one of claims 1 to 5, characterized in that: In a cascade of multiple RC polyphase filters, the output signal of the preceding RC polyphase filter (hereinafter referred to as the preceding stage) serves as the input signal of the succeeding RC polyphase filter (hereinafter referred to as the succeeding stage), and the preceding and succeeding stages are symmetrical about the horizontal axis. The in-phase differential signal output by the preceding stage is connected to the connection port between the first resistor R1 and the first capacitor C1, and the connection port between the third resistor R3 and the third capacitor C3, of the succeeding stage. The quadrature differential signal output by the preceding stage is connected to the connection port between the fourth resistor R4 and the fourth capacitor C4, and the connection port between the second resistor R2 and the second capacitor C2, of the succeeding stage. For each pair of poles, the connection port between the fourth capacitor C4 and the first resistor R1, and the connection port between the second capacitor C2 and the third resistor R3, of the succeeding stage serve as the output port for the in-phase differential signal. The connection port between the third capacitor C3 and the fourth resistor R4, and the connection port between the first capacitor C1 and the second resistor R2, serve as the output port for the quadrature differential signal. The connection wire lengths for the in-phase differential signal and the quadrature differential signal are the same.