Test circuit and test system for radio frequency circuit response time
By designing a test circuit including a coupler, a detector and an oscilloscope, the measurement process of the RF integrated circuit response time is simplified, the cost is reduced, and the measurement of the response time and other test items in the CP/FT test is achieved simultaneously.
Patent Information
- Application Number
- CN202422865125.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2034-11-22
AI Technical Summary
In the prior art, measuring the response time of RF integrated circuits requires specialized instruments and complex test solutions, which are costly. Furthermore, other tests cannot be performed within a specific timeframe, resulting in high time and hardware costs.
A test circuit is designed, including a coupler, a detector and an oscilloscope. The RF output signal is coupled by the coupler, converted into a DC voltage by the detector, and acquired by the oscilloscope. The controller triggers the oscilloscope to acquire the time difference, thereby realizing the measurement of the response time.
It simplifies the test process, reduces hardware and time costs, and can measure response time and other test items simultaneously in CP/FT testing, saving resources.
Smart Images
Figure CN223486126U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of radio frequency testing, and in particular to a test circuit and test system for the response time of radio frequency circuits. Background Technology
[0002] Radio frequency integrated circuits (RFICs) are electronic circuits that integrate radio frequency (RF) functions on a single chip. RFICs receive RF input signals, perform corresponding RF processing, and output RF output signals. During CP (Circuit Probing) and FT (Final Test) testing of RFICs, instruments capable of transmitting and receiving RF signals, such as vector network analyzers (VNAs), signal generators (SGs), and spectrum analyzers (SAs), are often used.
[0003] For radio frequency integrated circuits (RFICs) that can switch functions, operating modes, and states via digital signals, the input digital control signals control their operating states. Therefore, when the control signals received by the RFIC change, its operating state also changes or switches. However, in practice, the timing of this control signal change and the timing of the RFIC's operating state change are not synchronous; there is a brief delay (typically on the order of 10ns to 100ns). That is, the RFIC needs a response time (i.e., a delay) after receiving the control signal before changing its operating state.
[0004] In existing technologies, the measurement of response time generally requires specialized instruments, and the test scheme is complex with high hardware and software costs; in addition, the measurement must be carried out within a specific time period, during which other tests cannot be performed, resulting in high time costs. Utility Model Content
[0005] To address the issues of complexity and high cost in existing testing technologies, this application proposes a test circuit for the response time of radio frequency (RF) circuits. This circuit tests the RF circuit under test, which receives a control signal and outputs an RF output signal. The control signal controls the output state of the RF output signal; when the control signal changes, the output state of the RF output signal changes. The test circuit includes: a coupler, whose input terminal receives the RF output signal and couples it into a coupling signal; a detector, whose input terminal is connected to the coupling terminal of the coupler, which receives the coupling signal, converts it into a DC voltage, and outputs a detection voltage; an oscilloscope, whose input terminal is connected to the output terminal of the detector, which acquires the waveform of the detection voltage; and a controller, which sends the control signal to the control terminal of the RF circuit under test and sends a trigger signal to the control terminal of the oscilloscope. The trigger signal triggers the oscilloscope to acquire the waveform, which reflects the time difference between the change in the control signal and the change in the output state of the RF output signal.
[0006] Optionally, the controller includes:
[0007] The trigger module monitors changes in the control signal and generates the trigger signal when the control signal changes.
[0008] Optionally, the coupler is a directional coupler.
[0009] Optionally, the detector is an envelope detector or an average value detector.
[0010] Optionally, the detector is a detector integrated circuit.
[0011] Optionally, the radio frequency circuit under test includes a power amplifier or an attenuator, and the output state includes: a state that outputs the radio frequency output signal and a state that does not output the radio frequency output signal.
[0012] This application also proposes a testing system, including:
[0013] According to any of the aforementioned test circuits;
[0014] The radio frequency signal source has its output terminal connected to the input terminal of the radio frequency circuit, and is used to output the radio frequency signal to the radio frequency circuit.
[0015] Optionally, the radio frequency signal source is a vector network analyzer.
[0016] Optionally, the coupler includes an output terminal and a coupling terminal, the coupling terminal outputs the coupling signal, and the vector network analyzer is connected to the output terminal of the coupler for detecting the radio frequency output signal.
[0017] The test circuit sends a control signal to the RF circuit under test via a controller and a trigger signal to the oscilloscope. The trigger signal is used to trigger the oscilloscope to acquire the waveform. When the control signal changes, the output state of the RF output signal changes; a coupler couples the RF output signal into a coupling signal, and changes in the coupling signal reflect changes in the output state of the RF output signal; a detector detects the coupling signal and detects a DC detection voltage, which reflects changes in the output state of the RF output signal. The oscilloscope acquires the waveform of the detection voltage based on the trigger signal. The waveform reflects the time difference between the change in the control signal and the change in the output state of the RF output signal. In other words, the response time of the RF circuit under test can be measured based on the waveform acquired by the oscilloscope.
[0018] This test circuit allows for the testing of the response time of the RF circuit under test during CP / FT testing, eliminating the need for large instruments such as spectrum analyzers. The test circuit is simple, and the cost of response time testing itself is low.
[0019] Furthermore, by coupling the RF output signal through the coupler, the impact on the RF output signal is minimal. Therefore, other test items of the RF output signal can also be tested, such as VNA testing. In this case, the VNA can also be reused as a signal source, reducing time costs and saving resources. By coupling the coupled signal through the coupler, there is no need for a dedicated RF switch to switch between the detector and other test instruments, further reducing hardware costs.
[0020] The detector can be a detector integrated circuit, which has a very low cost and can save the overall cost of CP / FT testing. Attached Figure Description
[0021] Figure 1 This is a schematic diagram showing the relationship between the state switching and response time of a radio frequency integrated circuit.
[0022] Figure 2 This is a schematic diagram of the test circuit structure according to an embodiment of this application.
[0023] Figure 3 This is a schematic diagram of a response time test performed using a test circuit according to an embodiment of this application. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0025] First refer to Figure 1 This section explains the relationship between state switching and response time of radio frequency integrated circuits (RFICs). For example... Figure 1As shown, curve 101 is the time axis, curve 102 is the control signal received by the control pin of the RFIC, which can be a digital signal, and curve 103 is the voltage change curve of the output signal of the RF output pin of the RFIC. The time of curves 101, 102 and 103 changes synchronously.
[0026] In one embodiment, the RFIC can have two operating states, such as state A and state B. After an RF signal is input to the RFIC, when the control signal input to the RFIC is a low-voltage control signal (e.g., a binary signal 0 representing low voltage), the RFIC is in state A, and no RF output signal is output at the RF output terminal. When the control signal input to the RFIC is a high-voltage control signal (e.g., a binary signal 1 representing high voltage), the RFIC is in state B, and an RF output signal is output at the RF output terminal. It is understood that the correspondence between high and low voltage control signals and states A and B is merely an example; it could also be that a high-voltage control signal corresponds to state A, a low-voltage control signal corresponds to state B, or other more complex control scenarios. Furthermore, if no RF signal is input to the RFIC, there will be no output regardless of the RFIC's output state. The output state refers to whether an RF output signal is output when an RF input signal is input to the RFIC, and includes states A and B as described above.
[0027] For ease of explanation, in a specific example, the RFIC includes an amplifier (or attenuator). After an RF signal is input to the RFIC, when the control signal is low, the RFIC is in state A, and the amplifier (or attenuator) does not amplify (or attenuate), i.e., it does not output an RF output signal. When the control signal is high, the RFIC is in state B, and the amplifier (or attenuator) amplifies (or attenuates), i.e., it outputs an RF output signal. In other embodiments, when the RFIC is in state B, there is no signal output at the RF output terminal, i.e., no RF output signal is output; when the RFIC is in state A, the RF output terminal outputs a high-power signal, i.e., it outputs an RF output signal.
[0028] Therefore, when the control signal input to the RFIC changes, the output state of the RFIC's radio frequency output signal will also change. For example... Figure 1As shown, taking the switch from state A to state B as an example (i.e., the control signal changes from low voltage to high voltage), at time T1, the control signal switches from low voltage to high voltage (as shown by curve 102). After a certain period of time, at time T2, the output voltage of the RFIC's RF output terminal reaches 90% of the steady-state voltage of state B (as shown by curve 103). At this point, the RFIC's output state switch is considered complete, and the difference between T2 and T1 is the response time. Those skilled in the art will understand that when the control signal switches from high voltage to low voltage, for example, when the output power reaches 10% of state B, the RFIC's output state switch is considered complete.
[0029] Next reference Figure 2 The testing principle of the test circuit of this application will be explained. Figure 2 The circuit shown includes an RFIC under test 201 and a response time test circuit 202. The RFIC under test includes a control pin 2011, an RF input pin 2012, and an RF output pin 2013. The control pin 2011 of the RFIC under test is used to receive control signals to control the output state of the RFIC under test. When the control signal changes, the output state also changes accordingly. The RF input pin 2012 is used to receive the RF input signal input to the RFIC under test. The RF output pin 2013 outputs the corresponding RF output signal according to the output state.
[0030] The test circuit 202 includes a coupler 203, a detector 204, an oscilloscope 205, and a controller 206. The input of the coupler 203 receives the RF output signal from the RF output pin 2013 of the RFIC under test and couples it out as a coupling signal. The coupling signal reflects the state of the RF output signal, and its magnitude reflects the magnitude of the RF output signal. When there is no RF output signal, there is no coupling signal output; when there is an RF output signal, there is a coupling signal output; when the magnitude of the RF output signal is large, the magnitude of the coupling signal is also large.
[0031] The input terminal of detector 204 is connected to the coupling terminal of coupler 203 to receive the coupled signal coupled out by coupler 203, and uses the detection function to convert the coupled signal into DC voltage so that the output terminal of detector 204 outputs DC detection voltage. The magnitude of the detection voltage can reflect the magnitude of the coupled signal. When the magnitude of the coupled signal is large, the magnitude of the detection voltage is large.
[0032] The input terminal of oscilloscope 205 is connected to the output terminal of detector 204 to acquire the waveform of the detected voltage, which reflects the magnitude of the detected voltage. Oscilloscope 205 displays the waveform after receiving a trigger signal.
[0033] To ensure test timing, the test circuit 202 also includes a controller 206. The controller 206 is used to send control signals to the RFIC under test (DUT), specifically to the DUT's control pin 2011 (which can be understood as the DUT's control terminal), and to send a trigger signal to the control terminal of the oscilloscope 205. The trigger signal is used to trigger the oscilloscope to acquire waveforms, which reflect the time difference between the change in the control signal and the change in the output state of the RF output signal.
[0034] In some embodiments, when the control signal changes, the controller 206 sends a trigger signal to the oscilloscope at the same time. This trigger signal is used to trigger the oscilloscope to start acquiring the waveform of the detector voltage. Therefore, the starting point of the waveform is synchronized with the time point when the RF circuit under test receives the control signal. The waveform change points acquired by the oscilloscope can reflect the time points when the output state of the RF output signal changes. Therefore, based on the time difference between the starting point and the waveform change points, the time difference between the change of the control signal and the change of the output state of the RF output signal can be reflected. In other words, the response time of the RF circuit under test can be tested.
[0035] This test circuit allows for testing the response time of the RF circuit under test during CP / FT testing without the need for large instruments such as a spectrum analyzer. Both the coupler 203 and the detector 204 can be chip-level circuits, resulting in a simple test circuit with low hardware and software costs.
[0036] The coupler 203 in the test circuit 202 serves to isolate the signal and has little impact on the RF output signal. Therefore, other test items of the RF output signal can also be tested, reducing time costs. By coupling out the coupled signal through the coupler, there is no need for a dedicated RF switch to switch between the detector and other test instruments, further reducing hardware costs.
[0037] Coupler 203 can be a directional coupler, which can extract a small portion of the RF output signal for detection, and the remaining signal can be output to vector network analyzer 208 for analysis. Coupler 203 can include an output terminal and a coupling terminal. The coupling terminal outputs a coupled signal, and vector network analyzer 208 is connected to the output terminal of the coupler for detecting the RF output signal.
[0038] Detector 204 can be an envelope detector or an average value detector, or it can be a detector integrated circuit. Since detector integrated circuits are inexpensive and sufficient to meet test requirements, hardware costs can be reduced. In addition, detector integrated circuits can be integrated into RFICs and further integrated into test circuit boards used for RFIC testing, further improving the integration of the test system.
[0039] The configuration of controller 206 further ensures the alignment of the time point when the RFIC under test receives the change in the control signal and the time point when the oscilloscope begins acquisition on the time axis. Those skilled in the art will understand that, since the transmission speed of electrical signals is much higher than the response time, the time between the controller 206 issuing the control signal and the RFIC under test receiving the control signal is negligible relative to the response time. Furthermore, the trigger module 207 can be implemented in software or hardware, providing flexible and cost-effective triggering of the oscilloscope without affecting measurement accuracy.
[0040] Next, combine Figure 3 Let's further explain controller 206. For example... Figure 3 As shown, curve 301 is the time axis, curve 302 is the control signal received by the control pin of the RFIC, which can be a digital signal, and curve 303 is the voltage change curve of the output signal of the RF output pin of the RFIC. Under the action of the controller 206, the time of curves 301, 302 and 303 is automatically aligned.
[0041] When the response time test begins, at time t1, the controller sends a different control signal to the RFIC under test 201 than before; that is, the vertical bend of curve 302 widens (for example, when the original control signal received by control pin 2011 is low voltage, a control signal 1 indicating high voltage is input to it), to control it to change its operating state. Simultaneously, the trigger module 207 in the controller 206 also sends a trigger signal to the oscilloscope 205 at time t1 to begin acquiring the waveform of the detector voltage. This achieves alignment on the time axis between the time point when the RFIC under test 201 receives the control signal and the time point when the oscilloscope 205 begins acquiring the detector voltage (e.g., ...). Figure 3 (As shown by the dashed line at time point t1), this eliminates the need for other procedures or instruments to determine the time point, ensuring test timing, simplifying circuit structure and test procedures, and reducing hardware and software costs. At time point t2, when the detector voltage reaches 90% of the steady-state voltage, the output state of the tested RFIC 201 is considered to have changed. Therefore, the difference between t2 and t1 is the response time.
[0042] This application also proposes a testing system, such as Figure 2As shown, it includes the test circuit 202 described above and an RF signal source 208, wherein the output terminal of the RF signal source is connected to the input terminal (RF input pin 2012) of the RF circuit, and is used to output RF signals to the RF circuit. Under the action of the control signal, the RF circuit generates different output RF signals based on the RF signal. Since the Vector Network Analyzer (VNA) has built-in signal transmission and reception analysis functions, the RF signal source preferably uses a VNA (such as...). Figure 2 The VNA 208 shown continuously sends a point-frequency signal within the operating frequency band to the signal input port of the RFIC 201 under test, and can receive the RF signal (i.e., the main signal) output by the RFIC 201 under test from the coupler 203 to perform analysis and measurement of test items other than response time. However, since the VNA 202 cannot measure the relationship between voltage and time, it cannot measure the response time.
[0043] It is understood that the use of a VNA as the RF signal source is merely a preferred example, not a limitation, and other RF devices such as a signal generator (SG) can also be used. The main inventive point of this application lies in measuring the response time of an RFIC through a combination of a detector and an oscilloscope, and in controlling the RFIC state switching time and the oscilloscope start acquisition time by setting a controller.
[0044] The above description illustrates the implementation of this application through specific embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with preferred embodiments, this does not mean that the features of this utility model are limited to this embodiment. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0045] Furthermore, the various operations will be described as multiple discrete operations in a manner most conducive to understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations must depend on the order. In particular, these operations do not need to be performed in the order presented.
[0046] Unless the context otherwise specifies, the terms “contains,” “has,” and “includes” are synonyms. The phrase “A / B” means “A or B.” The phrase “A and / or B” means “(A and B) or (A or B).”
[0047] As used herein, the terms “module” or “unit” may refer to, be, or include: application-specific integrated circuits (ASICs), electronic circuits, (shared, dedicated, or group) processors and / or memories that execute one or more software or firmware programs, combinational logic circuits, and / or other suitable components that provide the described functionality.
[0048] In the accompanying drawings, certain structural or methodological features are shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. In some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.
[0049] It should be understood that although terms such as "first," "second," etc., may be used herein to describe various units or data, these units or data should not be limited by these terms. These terms are used merely to distinguish one feature from another. For example, without departing from the scope of the exemplary embodiments, a first feature may be referred to as a second feature, and similarly, a second feature may be referred to as a first feature.
[0050] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.
[0051] Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of the present invention.
Claims
1. A test circuit for the response time of radio frequency circuits, characterized in that, This test circuit is used to test a radio frequency (RF) circuit under test. The RF circuit under test receives a control signal and outputs an RF output signal. The control signal controls the output state of the RF output signal. When the control signal changes, the output state of the RF output signal changes. The test circuit includes: A coupler, whose input terminal receives the radio frequency output signal and couples the radio frequency output signal into a coupling signal; The detector has its input terminal connected to the coupling terminal of the coupler. It is used to receive the coupled signal, convert the coupled signal into a DC voltage, and output a detection voltage. An oscilloscope, with its input terminal connected to the output terminal of the detector, is used to acquire the waveform of the detected voltage; The controller is used to send the control signal to the control terminal of the RF circuit under test and to send a trigger signal to the control terminal of the oscilloscope. The trigger signal is used to trigger the oscilloscope to acquire the waveform, and the waveform reflects the time difference between the change of the control signal and the change of the output state of the RF output signal.
2. The test circuit according to claim 1, characterized in that, The controller includes: The trigger module is used to monitor changes in the control signal and generate the trigger signal when the control signal changes.
3. The test circuit according to claim 1 or 2, characterized in that, The coupler is a directional coupler.
4. The test circuit according to claim 1 or 2, characterized in that, The detector is an envelope detector or an average value detector.
5. The test circuit according to claim 1 or 2, characterized in that, The detector is a detector integrated circuit.
6. The test circuit according to claim 1 or 2, characterized in that, The tested radio frequency circuit includes a power amplifier or an attenuator, and the output state includes: a state that outputs the radio frequency output signal and a state that does not output the radio frequency output signal.
7. A testing system, characterized in that, include: The test circuit according to any one of claims 1 to 6; The radio frequency signal source has its output terminal connected to the input terminal of the radio frequency circuit, and is used to output the radio frequency signal to the radio frequency circuit.
8. The testing system according to claim 7, characterized in that, The radio frequency signal source is a vector network analyzer.
9. The testing system according to claim 8, characterized in that, The coupler includes an output terminal and a coupling terminal. The coupling terminal outputs the coupling signal. The vector network analyzer is connected to the output terminal of the coupler and is used to detect the radio frequency output signal.