A primary-secondary channel double demodulation measurement system and method based on unified internal reference

Abstract

The application discloses a primary and secondary channel double-demodulation measurement system and method based on unified internal reference, relates to the technical field of integrated circuits, and comprises an internal reference generation module, a primary input sampling module, an auxiliary input sampling module, a primary channel demodulation module, an auxiliary channel demodulation module, a link state control module and a result output module. The application provides a double-channel demodulation measurement system, which can enable the primary input and the auxiliary input to complete synchronous demodulation under unified internal reference and unified time semantics, and supports independent control of a primary measurement chain, an auxiliary measurement chain, a primary display chain and an auxiliary display chain, so that the stability of formal measurement, the human-computer experience of display refreshing and the repeatability of primary and secondary phase difference results are taken into account.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and in particular to a dual demodulation measurement system and method based on a unified internal reference for main and auxiliary channels. Background Technology

[0002] In many practical applications, in addition to the main measured input, a phase-locked loop (PLL) measurement system often needs to simultaneously acquire an auxiliary input signal. For example, the auxiliary input can come from a reference readback, an additional sensor, a compensation detection branch, an external monitoring branch, or a second measurement branch used for main-auxiliary comparison. In this case, the user typically needs not only to obtain the amplitude and phase of the main channel relative to the reference, but also the amplitude and phase of the auxiliary channel relative to the same reference, and further, to obtain the stable phase difference or vector difference between the main and auxiliary channels.

[0003] However, current technology suffers from inaccurate and unstable measurements. Summary of the Invention

[0004] The main objective of this application is to propose a dual demodulation measurement system and method based on a unified internal reference for main and auxiliary channels, so as to achieve phase-locked measurement stably and accurately.

[0005] To achieve the above objectives, one aspect of this application proposes a dual demodulation measurement system based on a unified internal reference and a primary / secondary channel. The system includes: an internal reference generation module, a primary input sampling module, an auxiliary input sampling module, a primary channel demodulation module, an auxiliary channel demodulation module, a link state control module, and a result output module; the primary channel includes the primary input sampling module and the primary channel demodulation module, and the auxiliary channel includes the auxiliary input sampling module and the auxiliary channel demodulation module. The internal reference generation module is used to generate an internal reference signal and generate orthogonal reference components. The main channel demodulation module is used to perform phase-sensitive demodulation of the main input sampling signal and the orthogonal reference component, and output the main channel measurement result after filtering, synchronous filtering, averaging or equivalent stabilization processing. The auxiliary channel demodulation module is used to perform phase-sensitive demodulation of the auxiliary input sampling signal and the orthogonal reference component, and after filtering and synchronization processing compatible with the main channel, outputs the measurement result of the auxiliary channel. The main channel demodulation module includes a main measurement chain and a main display chain; the auxiliary channel demodulation module includes an auxiliary measurement chain and an auxiliary display chain; the main measurement chain and the auxiliary measurement chain are used to output formal measurement results, and the main display chain and the auxiliary display chain are used to output interface refresh results; The link status control module is used to control the enable status of the main measurement chain, the main display chain, the auxiliary measurement chain and the auxiliary display chain respectively, and to silence the corresponding link when any link is closed; The result output module is used to output at least the X, Y, R, and phase results of the main channel, the X, Y, R, and phase results of the auxiliary channel, and the phase difference result calculated based on the windowed vector results of the main channel and the auxiliary channel.

[0006] In some embodiments, the link state control module is configured to silence the corresponding link by at least one of the following methods when any link is closed: maintaining a local reset, blocking sampling pulses, shielding data writing, or invalidating the output.

[0007] In some embodiments, both the main channel demodulation module and the auxiliary channel demodulation module use a demodulation reference signal processed by a unified reference alignment chain, so that the main channel demodulation module and the auxiliary channel demodulation module are established under the same clock domain, the same point beat, and the same synchronization semantics.

[0008] In some embodiments, the unified reference alignment chain includes a cross-clock domain buffer unit, a reference readout timing control unit, and a reference alignment unit that works in conjunction with a sampling synchronization flag; The internal reference signal is first generated in the high-frequency domain, then buffered and transferred to the demodulation clock domain, and output point by point in the demodulation clock domain according to the sampling synchronization beat to form an effective demodulation reference signal for use by the main channel and the auxiliary channel.

[0009] In some embodiments, the demodulation reference signal of the auxiliary channel adopts the reference component that has been time-aligned in the demodulation chain of the main channel, so as to ensure the consistency between the auxiliary channel and the main channel in terms of reference frequency, reference phase, clock domain position and sampling clock semantics.

[0010] In some embodiments, the main measurement chain, the main display chain, the auxiliary measurement chain, and the auxiliary display chain share the pre-stage demodulation infrastructure, but are separated in terms of the output aperture of the subsequent stage; wherein, the main display chain and the auxiliary display chain are used for refreshing, previewing, or human-computer interaction, and the main measurement chain and the auxiliary measurement chain are used for formally reading data, automatically testing, and calculating the main-auxiliary phase difference results.

[0011] In some embodiments, the main-auxiliary phase difference result is obtained based on the combination relationship between the main channel complex vector and the auxiliary channel complex vector within the same measurement window; Wherein, the main channel complex vector Represented as: ; in, Main channel in-phase component, The orthogonal components of the main channel The imaginary unit; The auxiliary channel complex vector Represented as: ; in, For auxiliary channel in-phase components, For auxiliary channel orthogonal components; The primary and secondary phase difference results Represented as: ; in, This represents the conjugate vector of the auxiliary channel complex vector; In low-frequency or ultra-low-frequency mode, the main measurement chain and the auxiliary measurement chain employ synchronous filtering, block integration, or long-time constant processing, while the main display chain and the auxiliary display chain retain preview output or shorter path output.

[0012] In some embodiments, the main channel is the main input demodulation channel, and the auxiliary channel is the AUX input demodulation channel.

[0013] In some embodiments, the result output module includes a processor system and a host computer interface.

[0014] To achieve the above objectives, another aspect of this application proposes a dual demodulation measurement method for primary and secondary channels based on a unified internal reference. This method is applied to a dual demodulation measurement system for primary and secondary channels based on a unified internal reference as described above, and includes the following steps: The reference component signal that has been time-aligned in the main channel demodulation chain is used as the demodulation reference signal of the auxiliary channel so that the auxiliary channel is consistent with the main channel in terms of reference frequency, reference phase, clock domain position and sampling clock semantics. The main display chain and main display chain of the main channel, as well as the auxiliary measurement chain and auxiliary display chain of the auxiliary channel, share the pre-stage demodulation basic structure, but are separated from each other in terms of the output aperture of the subsequent stage. The main-auxiliary phase difference result is obtained based on the combination relationship between the main channel complex vector and the auxiliary channel complex vector within the same measurement window.

[0015] The embodiments of this application include at least the following beneficial effects: This application provides a dual-channel demodulation measurement system and method based on a unified internal reference. The system includes an internal reference generation module, a main input sampling module, an auxiliary input sampling module, a main channel demodulation module, an auxiliary channel demodulation module, a link state control module, and a result output module. This application provides a dual-channel demodulation measurement system that enables synchronous demodulation of the main and auxiliary inputs under a unified internal reference and unified time semantics. It also supports independent control of the main measurement chain, auxiliary measurement chain, main display chain, and auxiliary display chain, thereby balancing the stability of the formal measurement, the user-friendly experience of display refresh, and the repeatability of the main-auxiliary phase difference results. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a single-phase phase-sensitive detector provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the biphase phase-sensitive detector provided in the embodiments of this application; Figure 3 An example structural diagram of a dual demodulation measurement system with primary and secondary channels based on a unified internal reference, provided in an embodiment of this application; Figure 4 A schematic diagram of the unified reference alignment chain structure provided in the embodiments of this application; Figure 5 This is a schematic diagram of the separation structure of the main channel formal measurement chain and display chain provided in the embodiments of this application; Figure 6 This is a schematic diagram of the separation structure between the auxiliary channel formal measurement chain and the display chain provided in the embodiments of this application; Figure 7 This is a schematic diagram of the main-auxiliary phase difference calculation process provided in an embodiment of this application; Figure 8 A schematic diagram of the link enable control and silencing mechanism provided in the embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0020] Before providing a detailed description of the embodiments of this application, some related technologies involved in the embodiments of this application will be described first, as follows: This application relates to the fields of precision electronic measurement and digital phase-locked loop (PLL) testing technology, specifically to a dual-channel synchronous demodulation measurement system and method suitable for lock-in amplifiers, dielectric loss testing equipment, impedance measurement equipment, and low-frequency weak signal detection equipment. More specifically, this application relates to a system architecture that performs parallel demodulation of the main input signal and the auxiliary input signal under the same internal reference system, and obtains the main channel measurement results, the auxiliary channel measurement results, and the phase difference between the two under a unified time semantic.

[0021] Most existing phase-locked loop (PLL) measurement systems are built around a single input channel. A typical approach involves generating a reference signal using an internal direct digital frequency synthesizer or an external reference source, sampling the measured input using analog-to-digital conversion, multiplying the sampled result by the quadrature components of the reference signal, and then processing it through low-pass filtering, synchronization filtering, and averaging to obtain measurements of X, Y, R, and phase. The specific principle is as follows: A phase-sensitive detector (PSD) can replace a high-Q bandpass filter. Its basic module consists of a multiplication module that multiplies the input signal with a reference signal and a filter module that performs a low-pass filter on the multiplication result, such as... Figure 1 As shown.

[0022] set up It is a time-domain input signal mixed with noise. A reference signal is a signal with the same frequency as the input signal under test. The term "reference signal" is crucial; it refers to the signal initially mixed (multiplied) with the input signal under test, and it shares the same frequency. In a bidirectional PSD, there are two reference signals with a 90° phase difference. The concept of the reference signal will appear frequently in later sections of this application. Combining the signal under test channel and the reference signal channel, a complete PSD signal modulation link can be formed. The signal Sig_in entering the PSD module from the signal channel can be defined as: ; in It is the frequency of the signal to be measured. It is the signal to be measured. It's doped noise.

[0023] The standard reference signal output from the reference signal channel can be defined as: ; The output obtained by multiplying the two signals is: ; ; ; The result of the above equation has three parts. From the time-domain expression, the first part... Includes the amplitude of the signal under test Reference signal amplitude and the phase difference between the input signal and the reference signal The cosine value of the input signal, which does not contain time t in its expression, can be considered a constant when both the useful part of the input signal and the reference signal are stable; this part represents the DC component of the output. (Second part) This can be considered as a second harmonic AC component with a frequency twice that of the original input signal. Part Three This is the product of the noise signal and the reference signal. Therefore, from the time domain perspective, the second and third parts are both sine waves, which are AC signals; while the first part is a DC signal. So it is easy to filter out the second and third parts by low-pass filtering, leaving only the first part.

[0024] On the other hand, from the spectrum perspective, the first part of the result is in the DC range, the second part is at twice the frequency of the reference signal, and the third part is the original random signal after... Spectrum shifting, taking white noise as an example, results in white noise. Therefore, inputting the result into a low-pass filter yields its DC component as follows: ; At this point, although the phase difference between the signal under test and the reference signal can be adjusted... This allows determining the amplitude of the signal under test, but the accuracy of this adjustment is difficult to guarantee. The biphase PSD modulation link effectively solves this problem, and its structure is as follows: Figure 2 As shown.

[0025] The reference channel generates two sinusoidal signals that are 90° out of phase, which are then multiplied by the input signal: , ; Let phase difference The output result can be calculated as follows: , ; make This yields the output amplitude, which is independent of the phase difference: ; The phase difference between the reference signal and the signal under test can be obtained by the following formula: ; The above is the entire modulation-demodulation process of the PSD algorithm, which can accurately restore the amplitude and phase information of the signal under test in complex noise backgrounds.

[0026] However, in many practical applications, in addition to the main measured input, the system often needs to simultaneously acquire an auxiliary input signal. For example, the auxiliary input can come from a reference readback, an additional sensor, a compensation detection branch, an external monitoring branch, or a second measurement branch used for main-auxiliary comparison. In this case, users typically need not only to obtain the amplitude and phase of the main channel relative to the reference, but also the amplitude and phase of the auxiliary channel relative to the same reference, and further obtain the stable phase difference or vector difference between the main and auxiliary channels. Existing solutions typically have the following shortcomings when handling such requirements: 1. Lack of unified reference semantics between the main channel and auxiliary channel. Although many systems can sample both the main input and auxiliary input simultaneously, the auxiliary channel is only read as the raw sampled value or simple monitoring value, and is not included in the demodulation, filtering, synchronization and output system consistent with the main channel, resulting in a lack of comparability between the two results.

[0027] 2. Even if the primary and secondary channels share the same source reference, it does not mean that they use the same "demodulation reference chain". Especially in FPGA systems, the reference signal often needs to undergo cross-clock domain buffering, readout alignment, and coordination with the sampling synchronization flag before it can form a truly effective reference for demodulation. If the secondary channel bypasses this alignment reference chain and directly uses the source reference or another reference branch with different timing semantics, it will cause amplitude attenuation, phase drift, or deterioration in repeatability.

[0028] 3. The primary and secondary phase difference is often obtained by stitching together the primary phase and secondary phase in the subsequent software. This method is easily affected by phase envelope, inconsistent refresh window, inconsistent display smoothing strategies, and phase jumps under low signal-to-noise ratio, making it difficult to form a stable and unified formal measurement caliber.

[0029] 4. Existing equipment often uses the "interface display caliber" and the "actual measurement caliber" interchangeably. To improve the user experience, the display path often incorporates features such as fast refresh, smooth averaging, outlier suppression, or preview branches. If the actual measurement results are directly taken from this display path, the problem of "stable display but imprecise metrological semantics" can easily occur.

[0030] 5. When the main channel link, auxiliary channel link, preview link, and synchronous filter link are all in operation, the links that are not participating in the current measurement task continue to flip and write, which will increase digital switching noise, wiring pressure, and mutual interference between links, thus affecting the measurement stability in low-frequency, high-sensitivity, and long-term constant scenarios.

[0031] Therefore, it is necessary to propose a new dual-channel demodulation measurement system that enables the main input and auxiliary input to complete synchronous demodulation under a unified internal reference and unified time semantics, and supports independent control of the main measurement chain, auxiliary measurement chain, main display chain and auxiliary display chain, thereby taking into account the stability of formal measurement, the human-machine experience of display refresh and the repeatability of the main and auxiliary phase difference results.

[0032] The purpose of this application is to provide a dual demodulation measurement system and method based on a unified internal reference for the main and auxiliary channels, in order to solve the problems in the prior art such as inconsistent reference systems for the main and auxiliary channels, inability to directly compare the results of the main and auxiliary channels, unstable phase difference calculation, mixing of display aperture and measurement aperture, and significant mutual interference when multiple links operate in parallel. This application aims to achieve the following objectives: 1. Demodulate both the main input signal and the auxiliary input signal based on the same internal reference source; 2. Enable auxiliary channels to reuse reference alignment links consistent with those of the primary channel, rather than simply reusing reference source outputs that are from the same source but out of sync; 3. Separate the display chain from the formal measurement chain for each channel to form a dual-output structure with different semantics but that can work together; 4. Stably acquire the main channel results, auxiliary channel results, and main-auxiliary phase difference results within a unified measurement window; 5. Enable the main measurement chain, main display chain, auxiliary measurement chain, and auxiliary display chain respectively, and put the corresponding links into a silent state when not needed; 6. Balancing formal measurement stability and real-time interface refresh in low-frequency, ultra-low-frequency, long-time constant, and strong power frequency interference scenarios.

[0033] This application provides a dual demodulation measurement system for main and auxiliary channels based on a unified internal reference. The system includes: an internal reference generation module, a main input sampling module, an auxiliary input sampling module, a main channel demodulation module, an auxiliary channel demodulation module, a link status control module, and a result output module; the main channel includes the main input sampling module and the main channel demodulation module, and the auxiliary channel includes the auxiliary input sampling module and the auxiliary channel demodulation module; The internal reference generation module is used to generate an internal reference signal and generate orthogonal reference components. The main channel demodulation module is used to perform phase-sensitive demodulation of the main input sampling signal and the orthogonal reference component, and output the main channel measurement result after filtering, synchronous filtering, averaging or equivalent stabilization processing. The auxiliary channel demodulation module is used to perform phase-sensitive demodulation of the auxiliary input sampling signal and the orthogonal reference component, and after filtering and synchronization processing compatible with the main channel, outputs the measurement result of the auxiliary channel. The main channel demodulation module includes a main measurement chain and a main display chain; the auxiliary channel demodulation module includes an auxiliary measurement chain and an auxiliary display chain; the main measurement chain and the auxiliary measurement chain are used to output formal measurement results, and the main display chain and the auxiliary display chain are used to output interface refresh results; The link status control module is used to control the enable status of the main measurement chain, the main display chain, the auxiliary measurement chain and the auxiliary display chain respectively, and to silence the corresponding link when any link is closed; The result output module is used to output at least the X, Y, R, and phase results of the main channel, the X, Y, R, and phase results of the auxiliary channel, and the phase difference result calculated based on the windowed vector results of the main channel and the auxiliary channel.

[0034] Optionally, the link status control module is used to silence the corresponding link by at least one of the following methods when any link is closed: maintaining a local reset, blocking sampling pulses, shielding data writing, or invalidating the output.

[0035] Optionally, both the main channel demodulation module and the auxiliary channel demodulation module use a demodulation reference signal processed by a unified reference alignment chain, so that the main channel demodulation module and the auxiliary channel demodulation module are established under the same clock domain, the same point beat, and the same synchronization semantics.

[0036] Optionally, the unified reference alignment chain includes a cross-clock domain buffer unit, a reference readout timing control unit, and a reference alignment unit that works in conjunction with a sampling synchronization flag; The internal reference signal is first generated in the high-frequency domain, then buffered and transferred to the demodulation clock domain, and output point by point in the demodulation clock domain according to the sampling synchronization beat to form an effective demodulation reference signal for use by the main channel and the auxiliary channel.

[0037] Optionally, the demodulation reference signal of the auxiliary channel adopts the reference component that has been time-aligned in the demodulation chain of the main channel, so as to ensure the consistency between the auxiliary channel and the main channel in terms of reference frequency, reference phase, clock domain position and sampling clock semantics.

[0038] Optionally, the main measurement chain, the main display chain, the auxiliary measurement chain, and the auxiliary display chain share the pre-stage demodulation infrastructure, but are separated in terms of the output aperture of the subsequent stage; wherein, the main display chain and the auxiliary display chain are used for refreshing, previewing, or human-computer interaction, and the main measurement chain and the auxiliary measurement chain are used for formally reading data, automatically testing, and calculating the main-auxiliary phase difference results.

[0039] Optionally, the main-auxiliary phase difference result is obtained based on the combination relationship between the main channel complex vector and the auxiliary channel complex vector within the same measurement window; Wherein, the main channel complex vector Represented as: ; in, Main channel in-phase component, The orthogonal components of the main channel The imaginary unit; The auxiliary channel complex vector Represented as: ; in, For auxiliary channel in-phase components, For auxiliary channel orthogonal components; The primary and secondary phase difference results Represented as: ; in, This represents the conjugate vector of the auxiliary channel complex vector; In low-frequency or ultra-low-frequency mode, the main measurement chain and the auxiliary measurement chain employ synchronous filtering, block integration, or long-time constant processing, while the main display chain and the auxiliary display chain retain preview output or shorter path output.

[0040] Optionally, the main channel is the main input demodulation channel, and the auxiliary channel is the AUX input demodulation channel.

[0041] Optionally, the result output module includes a processor system and a host computer interface.

[0042] This application also proposes a dual demodulation measurement method for primary and secondary channels based on a unified internal reference. The method is applied to the dual demodulation measurement system for primary and secondary channels based on a unified internal reference as described above, and includes the following steps: The reference component signal that has been time-aligned in the main channel demodulation chain is used as the demodulation reference signal of the auxiliary channel so that the auxiliary channel is consistent with the main channel in terms of reference frequency, reference phase, clock domain position and sampling clock semantics. The main display chain and main display chain of the main channel, as well as the auxiliary measurement chain and auxiliary display chain of the auxiliary channel, share the pre-stage demodulation basic structure, but are separated from each other in terms of the output aperture of the subsequent stage. The main-auxiliary phase difference result is obtained based on the combination relationship between the main channel complex vector and the auxiliary channel complex vector within the same measurement window.

[0043] The following sections will provide a detailed description and explanation of some optional embodiments of this application, using specific application examples.

[0044] Specifically, this application provides a dual demodulation measurement system for the main channel and auxiliary channel based on a unified internal reference, including an internal reference generation module, a main input sampling module, an auxiliary input sampling module, a main channel demodulation module, an auxiliary channel demodulation module, a link state control module, and a result output module, wherein: The internal reference generation module is used to generate internal reference signals and generate orthogonal reference components; The main channel demodulation module is used to perform phase-sensitive demodulation of the main input sampling signal and the orthogonal reference component. After filtering, synchronous filtering, averaging or equivalent stabilization processing, the main channel measurement result is output. The auxiliary channel demodulation module is used to perform phase-sensitive demodulation of the auxiliary input sampling signal and the orthogonal reference component. After filtering and synchronization processing compatible with the main channel, the auxiliary channel measurement results are output. Neither the main channel demodulation module nor the auxiliary channel demodulation module directly uses the original output of the reference source. Instead, they use the demodulation reference processed by the unified reference alignment chain to ensure that the main and auxiliary channels are established under the same clock domain, the same point tick, and the same synchronization semantics. The main channel and the auxiliary channel each include at least one formal measurement chain and one display chain. The formal measurement chain is used to output the formal measurement results, and the display chain is used to output the interface refresh results. The link status control module is used to control the enable status of the main measurement chain, main display chain, auxiliary measurement chain and auxiliary display chain respectively, and when any link is closed, it silences the corresponding link by at least one of the following methods: maintaining local reset, blocking sampling pulse, shielding data writing or invalidating output. The results output module is used to output at least the X, Y, R, and phase results of the main channel, the X, Y, R, and phase results of the auxiliary channel, and the phase difference result calculated based on the windowed vector results of the main channel and the auxiliary channel.

[0045] It should be further explained that the unified reference alignment chain includes a cross-clock domain buffer unit, a reference readout timing control unit, and a reference alignment unit that works in conjunction with the sampling synchronization flag. The internal reference is first generated in the high-frequency domain, then buffered and transferred to the demodulation clock domain, and output point by point in the demodulation clock domain according to the sampling synchronization beat to form an effective demodulation reference for use by the main channel and the auxiliary channel.

[0046] In addition, the demodulation reference of the auxiliary channel adopts the reference component that has been time-aligned in the demodulation chain of the main channel to ensure the consistency between the auxiliary channel and the main channel in terms of reference frequency, reference phase, clock domain position and sampling clock semantics.

[0047] Then, the formal measurement chains and display chains of the main channel and auxiliary channel share the pre-amplifier demodulation infrastructure, but are separated in terms of output aperture in the post-amplifier stage; the display chain is used for fast refresh, preview or human-computer interaction, while the formal measurement chain is used for formal data reading, automatic testing and main-auxiliary phase difference calculation.

[0048] Finally, the main-auxiliary phase difference result is not obtained by simply subtracting independent phase values, but rather based on the combination relationship between the main channel complex vector and the auxiliary channel complex vector within the same measurement window. The main channel complex vector can be expressed as: ; The auxiliary channel complex vector can be represented as: ; The principal-slave phase difference can then be expressed as: ; in, This represents the conjugate of the auxiliary channel complex vector. In low-frequency or ultra-low-frequency modes, the formal measurement chain employs synchronous filtering, block integration, or long-time constant processing, while the display chain retains the preview output or the shorter path output, thus balancing formal measurement stability with interface response speed.

[0049] For example, an optional implementation includes the following technical solution: 1. Overall System Implementation: This implementation uses a programmable logic unit and a processor system to form a dual-channel demodulation and measurement system. The programmable logic unit is used to complete internal reference generation, reference alignment, primary and secondary channel demodulation, and result output; the processor system is used to complete parameter configuration, link control, result reading, and interaction with the host computer.

[0050] In a preferred embodiment, the main channel is the main input demodulation channel, and the auxiliary channel is the AUX input demodulation channel. Although the main channel and the auxiliary channel may use different sampling front-ends, they both operate under a unified internal reference architecture. The main channel may use an ADC with a higher sampling rate and higher resolution, while the auxiliary channel may use an auxiliary ADC with a lower sampling rate; for example, the main channel may use an ADS1675, and the auxiliary channel may use an LTC2353. It should be noted that the device model, bit depth, and sampling rate are only examples of preferred embodiments, and the embodiments in this application are not limited to specific devices.

[0051] like Figure 3 As shown, the overall structure of this application embodiment includes an internal reference generation and reference alignment module, a main input sampling module, an auxiliary input sampling module, a main channel demodulation module, an auxiliary channel demodulation module, a main and auxiliary phase difference calculation module, and a processor system and a host computer interface.

[0052] 2. Unified internal reference and reference alignment implementation method: In this embodiment, the internal reference is generated by a digital reference source and, after cross-clock domain buffering and demodulation clock domain alignment, forms a valid demodulation reference. The main channel uses this aligned reference to complete phase-sensitive demodulation; the auxiliary channel does not reconstruct another set of independent reference semantics, but instead reuses the reference components that the main channel has already aligned for demodulation.

[0053] Therefore, the embodiments of this application emphasize not a simple "same source reference," but rather that the main channel and auxiliary channel share the "same reference alignment chain." Even if the front-end sampling hardware of the main channel and auxiliary channel are different, as long as the auxiliary channel data is mapped to a unified demodulation beat semantics, it can still form a directly comparable demodulation result with the main channel. Figure 4 As shown, the unified reference alignment chain can be composed of reference generation, cross-clock domain buffering, reference readout and clock timing, and alignment with the sampling synchronization flag. Its output aligned reference quadrature components are used by both the main channel and the auxiliary channel.

[0054] 3. Implementation method for separating the measurement chain and the display chain: In this embodiment, both the main channel and the auxiliary channel include at least two types of output paths: a formal measurement chain and a display chain. The formal measurement chain is used to output the formal measurement results, while the display chain is used to output the interface refresh results. The formal measurement results and the display results are stored or output separately, thereby avoiding the influence of interface smoothing strategies, preview strategies, or fast refresh strategies on the formal measurement caliber.

[0055] This separation structure is particularly suitable for low-frequency, long-time constant, and weak signal scenarios. The system can ensure result stability through the formal measurement chain and maintain good interface response speed through the display chain. Figure 5As shown, the formal measurement chain and display chain of the main channel share the pre-stage demodulation infrastructure, but are separated from each other in terms of the output aperture of the back stage. The formal measurement chain focuses more on stable, unified and traceable measurement semantics, while the display chain focuses more on fast interface refresh.

[0056] like Figure 6 As shown, the auxiliary channel is also equipped with a formal measurement chain and a display chain, and its demodulation reference preferably directly reuses the reference component that has been aligned in the main channel, so as to ensure that the results of the auxiliary channel and the results of the main channel can be directly compared.

[0057] 4. Implementation method of primary and secondary phase difference: In this embodiment, the main-auxiliary phase difference is preferably obtained based on the complex vector relationship between the main channel formal measurement chain and the auxiliary channel formal measurement chain, rather than by directly subtracting two independent phase values.

[0058] Assume the main channel formal measurement chain output is The auxiliary channel formal measurement chain output is Then it can be constructed as follows: , The primary-secondary phase difference can be expressed as: .

[0059] The above method allows the primary and secondary phase differences to be established based on a vector relationship within the same measurement window, thereby improving the consistency and stability of the results. For example... Figure 7 As shown, the calculation process of the main and auxiliary phase difference can be summarized as follows: first, obtain the X and Y outputs of the main measurement chain and the auxiliary measurement chain respectively; then, construct the main complex vector and the auxiliary complex vector; finally, obtain the main and auxiliary phase difference through the combination relationship of the complex vectors.

[0060] 5. Link enable and silent control implementation methods: In this embodiment, the system sets up independent enable control for the main measurement chain, main display chain, auxiliary measurement chain, and auxiliary display chain. When a certain chain is not participating in the current measurement task, the system does not simply stop displaying its results, but instead puts the chain into a silent state through partial reset, output zeroing, stopping sampling pulses, writing shield, or a combination thereof.

[0061] This setting helps reduce digital interference caused by continuous flipping of unused links, and is particularly beneficial for maintaining stable formal measurement results in low-frequency and high-stability measurement scenarios. For example... Figure 8 As shown, the link status control module can enable and manage the main measurement link, main display link, auxiliary measurement link, and auxiliary display link respectively; when a link is shut down, the system reduces the impact of invalid links on valid measurement links through a silent mechanism.

[0062] 6. An example of a measurement process: In one embodiment, the measurement process of this application may include the following steps: 1) Configure internal reference frequency, filtering parameters, synchronization mode, and link enable status; 2) Generate internal references and complete reference alignment; 3) The main channel uses the aligned reference to complete demodulation, and the official measurement results and display results of the main channel are obtained; 4) The auxiliary channel reuses this alignment reference to complete demodulation, obtaining the formal measurement and display results of the auxiliary channel; 5) The processor system reads the formal measurement chain results and calculates the amplitude, phase, and primary-secondary phase difference; 6) Output the formal measurement results, display results, or auxiliary input results to the host computer as needed.

[0063] In the above process, if a link is shut down, the corresponding link enters a silent state and does not participate in the current measurement task.

[0064] 7. The core inventive points of the embodiments of this application can be further refined into the following: 1) The main channel and the auxiliary channel do not only share the same internal reference source, but also share the same reference chain that has been completed with cross-clock domain buffering, clock timing adjustment and sampling synchronization alignment; 2) The auxiliary channel does not only output raw sampled values ​​or simple monitoring values, but enters a formal demodulation system compatible with the main channel; 3) Both the main channel and the auxiliary channel separate the formal measurement chain from the display chain, so that the formal measurement results are not affected by the interface refresh strategy; 4) The primary and secondary phase difference is preferably obtained from the complex vector relationship within the same measurement window, rather than from the direct subtraction of two independent phase values; 5) The system sets enable and mute controls for the main measurement chain, main display chain, auxiliary measurement chain, and auxiliary display chain respectively to reduce interference from unused links to effective measurement chains.

[0065] 8. Compared with existing solutions, the most critical difference in this application's embodiment is not the addition of an auxiliary input, but the establishment of reference semantics, demodulation semantics, and output semantics consistent with the main channel for the auxiliary input. In traditional solutions, even if the auxiliary channel shares a common source reference with the main channel, they often do not share the same reference alignment chain, so the main and auxiliary results cannot be directly compared in a strict sense; however, this application's embodiment establishes the main channel results, auxiliary channel results, and main-auxiliary difference results on a unified standard.

[0066] 9. Explanation of Technological Evolution and Verification Phenomena: The embodiments in this application are not directly derived from a single module, but rather formed during the gradual evolution of existing systems. The technological evolution process can be summarized as follows: 1) In the initial stage, the system is mainly designed around the main channel demodulation chain, focusing on solving the problems of internal reference demodulation, filtering and output; 2) Subsequently, to meet the needs of more measurement scenarios, an auxiliary input channel was introduced, aiming to obtain the amplitude and phase results of the auxiliary input relative to the same reference; 3) During the implementation process, it was found that if the auxiliary channel only shares the reference source but does not reuse the aligned reference chain actually used by the main channel, the results of the main and auxiliary channels are difficult to maintain strict consistency in engineering. 4) Furthermore, it was found that if the display chain and the formal measurement chain are used interchangeably, it will cause a mutual constraint between the stability of the interface refresh and the accuracy of the formal measurement. 5) When multiple links are working in parallel, it was also found that links not participating in the current task continue to flip, which causes additional interference to low-frequency and high-stability measurements.

[0067] Based on the above process, the current complete solution was gradually formed, namely: unified reference alignment chain, master and auxiliary dual demodulation, separation of measurement chain and display chain, calculation of master and auxiliary complex vector phase difference, and link silence control.

[0068] During the verification process, a representative phenomenon was observed: if the auxiliary channel did not reuse the reference chain aligned with the main channel, but instead used a reference of the same origin but not synchronized, problems often arose such as the auxiliary channel phase appearing roughly correct, but the `X / Y / R` values ​​being too small, insufficient stability of repeated measurements, and easy drift in the main-auxiliary difference results. This phenomenon indicates that the "unified reference alignment chain" in the embodiments of this application is not optional, but rather the key to achieving a unified measurement aperture between the main and auxiliary channels.

[0069] 10. The embodiments of this application may be applied to, but are not limited to, the following scenarios: 1) Main channel standalone formal measurement scenario; 2) Simultaneous measurement scenario of main channel and auxiliary channel; 3) Primary and secondary phase difference measurement scenario; 4) Stable measurement scenarios at low frequency, ultra-low frequency, or long time constants; 5) Reference readback, sensor comparison, compensation branch monitoring, and other multi-input common reference demodulation scenarios.

[0070] It should also be noted that the embodiments of this application are not limited to a specific device or a unique implementation. For example: 1) The internal reference source is not limited to a certain DDS implementation, as long as a unified reference and its alignment chain can be formed; 2) The auxiliary channel is not limited to a single AUX input; it can also be expanded to multiple auxiliary inputs. 3) The auxiliary channel is not limited to a specific sampling rate or a specific resolution, as long as it can be mapped to a unified demodulation semantics; 4) Link silence control is not limited to local reset; it can also be achieved by stopping sampling pulses, masking writes, clearing outputs, invalidating results, or a combination thereof. 5) The calculation of the principal-auxiliary phase difference can be implemented on both the processor system side and the programmable logic side. The key is that it is based on the principal-auxiliary complex vector relationship within a unified measurement window.

[0071] 11. During the formation of the embodiments of this application, the following engineering observations played an important role in confirming the inventive points: 1) When the auxiliary channel uses a reference that is from the same source as the main channel but does not pass through the same alignment chain, the auxiliary channel result is not necessarily completely wrong, but it often manifests as smaller `X / Y / R` values, repeated measurement drift, or unstable main-auxiliary difference. 2) In this case, the phase value sometimes looks roughly reasonable, so it is easy to mistakenly judge that the auxiliary channel is "usable". However, when further comparing the results of the main and auxiliary vectors, it will be found that they are not in the same strict range as the results of the main channel. 3) When the auxiliary channel is replaced with a reference chain that has already been aligned with the main channel, the consistency, repeatability, and phase difference stability of the main and auxiliary results will be significantly improved. 4) When the display chain and the formal measurement chain are used together, the stability of the interface refresh and the accuracy of the formal measurement are easily mutually constrained; however, by separating the two, the needs of both formal measurement and interface display can be better balanced. 5) When multiple links are enabled simultaneously and no quiescent control is implemented for unused links, additional fluctuations are more likely to be observed in low-frequency and high-stability scenarios; after introducing link quiescent control, the stability of the formal measurement link is more easily maintained.

[0072] The above phenomena are only used to illustrate that several key design points in the embodiments of this application are driven by explicit engineering problems, rather than arbitrary splicing and combination. In particular, the necessity of the "unified reference alignment chain" is gradually confirmed through the above phenomena.

[0073] In summary, the key technical solutions of the embodiments of this application include the following structured compositional relationships and their measurement semantics: 1. "Unified internal reference" is further defined as "unified reference alignment chain". That is, the embodiments of this application emphasize that the main channel and auxiliary channel do not merely share the same reference source, but rather share the same demodulation reference chain after cross-clock domain buffering, clock timing adjustment, and sampling synchronization alignment. This effectively distinguishes it from common schemes that only share the same reference source but whose actual demodulation timing is inconsistent.

[0074] 2. Integrate the auxiliary channel into a formal demodulation system consistent with the main channel. The auxiliary channel is not output separately as raw sampled monitoring data, but rather enters a multiplication demodulation, filtering, synchronization, and result output system compatible with the main channel, thereby ensuring that the results of the main channel, the results of the auxiliary channel, and the differences between the two all have unified metrological semantics.

[0075] 3. Clear separation of display chain and formal measurement chain. Traditional systems often default to only one result output, while the embodiments of this application explicitly separate "human-machine interface refresh" and "formal measurement caliber" into different chains, and allow the main channel and auxiliary channel to be set with display output and measurement output respectively. This structure is not a simple software display strategy, but a system-level output design that runs through PL and PS.

[0076] 4. The phase difference between the primary and secondary channels is not obtained by subtracting two independent phase values, but rather based on the complex vector relationship within the same measurement window. This processing method is more suitable for synchronous measurement scenarios with a common reference between the primary and secondary channels, and can reduce the impact of envelope angle, refresh asynchrony, and low-amplitude jitter on the stability of the results.

[0077] 5. Independent enable and silent mechanisms are introduced for the main measurement chain, main display chain, auxiliary measurement chain, and auxiliary display chain. The purpose is not ordinary switching control, but to reduce the digital flipping interference of unused links on the main measurement chain, so that the system can still maintain repeatable measurements in low-frequency and high-stability scenarios.

[0078] 6. This architecture inherently supports unified demodulation of heterogeneous sampling rate inputs. Even if the ADC resolution, sampling rate, and interface type of the main channel and auxiliary channel are different, as long as the auxiliary channel data is mapped to a unified demodulation timing semantic, comparable main-auxiliary demodulation results can still be obtained. This makes the embodiments of this application clearly practical for engineering and scalable.

[0079] Therefore, the more accurate innovation of the embodiments of this application should be described as follows: Under the condition of heterogeneous input hardware, a system-level measurement scheme that can stably output the main channel results, auxiliary channel results and main-auxiliary difference results is formed by unifying the internal reference alignment chain, main and auxiliary parallel demodulation, separating the display chain and the measurement chain, calculating the main and auxiliary complex vector difference, and controlling the link on demand.

[0080] Compared with the prior art, the embodiments of this application have at least the following beneficial effects: 1. By establishing a unified internal reference and a unified reference alignment chain, the main input and auxiliary input can be demodulated under the same semantic conditions at the same time, which improves the consistency and comparability of the main and auxiliary results.

[0081] 2. By requiring auxiliary channels to reuse the same aligned reference chain as the main channel, rather than simply sharing the reference source, the problems of small amplitude, phase drift, and insufficient repeatability caused by cross-clock domain, reference misalignment, and inconsistent sampling timing can be significantly reduced.

[0082] 3. By setting independent link control for the main measurement chain, main display chain, auxiliary measurement chain, and auxiliary display chain, interference to the formal measurement chain caused by the continuous flipping of unused links can be avoided, which is especially suitable for low-frequency high-precision measurements.

[0083] 4. By separating the display chain from the formal measurement chain, the consistency and traceability of the formal measurement caliber can be guaranteed without sacrificing the interface refresh effect.

[0084] 5. By obtaining the principal and auxiliary phase difference based on the relationship between the complex vectors within the same window, rather than simply calculating the angle difference, the errors caused by the change in the envelope angle and the inconsistency of the window can be reduced, thus improving the stability of the principal and auxiliary phase difference.

[0085] 6. The embodiments of this application can be extended to lock-in amplification, reference readback, low-frequency dielectric loss testing, impedance analysis, sensor comparison measurement, and other precision measurement scenarios that require multi-input common reference demodulation.

[0086] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0087] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0088] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0089] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0090] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A dual demodulation measurement system with primary and secondary channels based on a unified internal reference, characterized in that, The system includes: an internal reference generation module, a main input sampling module, an auxiliary input sampling module, a main channel demodulation module, an auxiliary channel demodulation module, a link status control module, and a result output module; the main channel includes the main input sampling module and the main channel demodulation module, and the auxiliary channel includes the auxiliary input sampling module and the auxiliary channel demodulation module; The internal reference generation module is used to generate an internal reference signal and generate orthogonal reference components. The main channel demodulation module is used to perform phase-sensitive demodulation of the main input sampling signal and the orthogonal reference component, and output the main channel measurement result after filtering, synchronous filtering, averaging or equivalent stabilization processing. The auxiliary channel demodulation module is used to perform phase-sensitive demodulation of the auxiliary input sampling signal and the orthogonal reference component, and after filtering and synchronization processing compatible with the main channel, outputs the measurement result of the auxiliary channel. The main channel demodulation module includes a main measurement chain and a main display chain; the auxiliary channel demodulation module includes an auxiliary measurement chain and an auxiliary display chain; the main measurement chain and the auxiliary measurement chain are used to output formal measurement results, and the main display chain and the auxiliary display chain are used to output interface refresh results; The link status control module is used to control the enable status of the main measurement chain, the main display chain, the auxiliary measurement chain and the auxiliary display chain respectively, and to silence the corresponding link when any link is closed; The result output module is used to output at least the X, Y, R, and phase results of the main channel, the X, Y, R, and phase results of the auxiliary channel, and the phase difference result calculated based on the windowed vector results of the main channel and the auxiliary channel.

2. The dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to claim 1, characterized in that, The link status control module is used to silence the corresponding link by at least one of the following methods when any link is closed: maintaining local reset, blocking sampling pulses, shielding data writing, or invalidating output.

3. The dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to claim 1, characterized in that, Both the main channel demodulation module and the auxiliary channel demodulation module use demodulation reference signals processed by a unified reference alignment chain, so that the main channel demodulation module and the auxiliary channel demodulation module are established under the same clock domain, the same point beat, and the same synchronization semantics.

4. The dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to claim 3, characterized in that, The unified reference alignment chain includes a cross-clock domain buffer unit, a reference readout timing control unit, and a reference alignment unit that works in conjunction with the sampling synchronization flag; The internal reference signal is first generated in the high-frequency domain, then buffered and transferred to the demodulation clock domain, and output point by point in the demodulation clock domain according to the sampling synchronization beat to form an effective demodulation reference signal for use by the main channel and the auxiliary channel.

5. The dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to claim 4, characterized in that, The demodulation reference signal of the auxiliary channel adopts the reference component that has been time-aligned in the demodulation chain of the main channel, so as to ensure the consistency between the auxiliary channel and the main channel in terms of reference frequency, reference phase, clock domain position and sampling clock semantics.

6. The dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to claim 5, characterized in that, The main measurement chain, the main display chain, the auxiliary measurement chain, and the auxiliary display chain share the pre-stage demodulation infrastructure, but are separated in terms of output aperture. The main display chain and the auxiliary display chain are used for refreshing, previewing, or human-computer interaction, while the main measurement chain and the auxiliary measurement chain are used for formally reading data, automatically testing, and calculating the main-auxiliary phase difference results.

7. The dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to claim 6, characterized in that, The main-auxiliary phase difference result is obtained based on the combination relationship between the main channel complex vector and the auxiliary channel complex vector within the same measurement window; Wherein, the main channel complex vector Represented as: ； in, The in-phase component of the main channel, The orthogonal components of the main channel The imaginary unit; The auxiliary channel complex vector Represented as: ； in, For auxiliary channel in-phase components, For auxiliary channel orthogonal components; The primary and secondary phase difference results Represented as: ； in, This represents the conjugate vector of the auxiliary channel complex vector; In low-frequency or ultra-low-frequency mode, the main measurement chain and the auxiliary measurement chain employ synchronous filtering, block integration, or long-time constant processing, while the main display chain and the auxiliary display chain retain preview output or shorter path output.

8. The dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to claim 1, characterized in that, The main channel is the main input demodulation channel, and the auxiliary channel is the AUX input demodulation channel.

9. A dual demodulation measurement system for primary and secondary channels based on a unified internal reference according to any one of claims 1 to 8, characterized in that, The result output module includes a processor system and a host computer interface.

10. A dual demodulation measurement method for primary and secondary channels based on a unified internal reference, characterized in that, The method is applied to a dual demodulation measurement system with primary and secondary channels based on a unified internal reference as described in claim 1, and the method includes the following steps: The reference component signal that has been time-aligned in the main channel demodulation chain is used as the demodulation reference signal of the auxiliary channel so that the auxiliary channel is consistent with the main channel in terms of reference frequency, reference phase, clock domain position and sampling clock semantics. The main display chain and main display chain of the main channel, as well as the auxiliary measurement chain and auxiliary display chain of the auxiliary channel, share the pre-stage demodulation basic structure, but are separated from each other in terms of the output aperture of the subsequent stage. The main-auxiliary phase difference result is obtained based on the combination relationship between the main channel complex vector and the auxiliary channel complex vector within the same measurement window.

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