Loop response test using MSO6 series oscilloscope

Loop response test is a common method for evaluating system stability and performance. It determines whether the system can work properly by measuring the frequency response and phase response of the system to the input signal. Loop response test is very important for many application fields, such as power management, motor control, robotics, aerospace, etc.

Control system block diagram & Bode diagram

Low noise is an important factor in loop testing because noise affects the quality of the signal and the accuracy of the measurement. Noise can come from many sources, such as the test signal itself, the test equipment, environmental interference, etc. Therefore, choosing an oscilloscope with low noise performance is a key step in loop testing.

The low noise advantages of the MSO6 series oscilloscope in loop testing are mainly reflected in the following aspects:

• Advanced noise suppression technology: MSO6 series oscilloscopes use advanced noise suppression technology, such as digital signal processing technology, which can effectively reduce the inherent noise generated inside the oscilloscope. This technology can reduce the interference of noise on test results and improve test accuracy.

• Optimized hardware design: The MSO6 series oscilloscope also takes low noise into full consideration in its hardware design. For example, it may use low-noise amplifiers and filters, which can reduce the noise component in the input signal and thus improve the signal-to-noise ratio. In addition, the probe and cable design may also use low-noise technology to ensure that the noise introduced during the test is as small as possible.

• The 6 Series MSO features a new front-end ASIC, the TEK061, which achieves breakthrough noise performance at the highest sensitivity settings.

• Flexible trigger and measurement functions: MSO6 series oscilloscopes provide flexible trigger and measurement functions, which help engineers capture key signals and reduce the impact of random noise in loop testing. By adjusting the trigger mode and trigger source, engineers can select the best trigger conditions to capture and analyze signals more accurately.

• Powerful signal processing capability: MSO6 series oscilloscopes also have powerful signal processing capabilities, which can perform a variety of analyses and processing on the collected signals, such as spectrum analysis, filtering, etc. These functions not only help engineers to have a deeper understanding of the characteristics of the signal, but also can further reduce the impact of noise on the test results.

Noise Performance Comparison

综上所述，MSO6系示波器在环路测试中具有显著的低噪声优势，能够为工程师提供准确、可靠的测试结果，帮助他们更好地分析和评估系统的性能。

The Spectrum View function on the MSO6 series oscilloscope enables the patented technology built into the oscilloscope, allowing users to simultaneously view time domain analog waveforms and spectrum observations through the hardware in the instrument and independently control each domain. This function provides engineers and researchers with a powerful tool for analyzing complex signals and debugging system problems.

When using the Spectrum View function, users can control the time domain and frequency domain independently, which means that the center frequency, bandwidth and RBW can be set using familiar operations without affecting the time scale in the waveform view. Vice versa, changes in the horizontal scale will not affect the spectrum. This control method makes adjusting the spectrum more convenient and intuitive.

• Simultaneous observation of spectrum and time domain: SpectrumView technology enables engineers to observe the spectrum and time domain waveform of the signal on the same interface. This is crucial for loop response testing, because loop response involves the frequency response and phase response of the signal. Simultaneous observation of spectrum and time domain waveform helps to more fully understand the performance of the system.

• Enhanced frequency resolution: Through the unique Spectrum View technology, the MSO6 series oscilloscopes can provide higher frequency resolution, which is especially important for loop response testing where parameters such as crossover frequency and phase margin need to be accurately measured. High frequency resolution can ensure the accuracy of measurement results and help engineers more accurately evaluate the stability and performance of the system.

• Mixed signal analysis capability: The MSO6 series oscilloscope supports mixed signal analysis, which means it can process analog and digital signals at the same time. In loop response testing, this capability enables engineers to more easily analyze complex systems that contain both analog and digital parts, thereby gaining a more comprehensive understanding of the system's behavior.

• Advanced measurement functions: MSO6 series oscilloscopes are equipped with a series of advanced measurement functions, including phase margin, gain margin, crossover frequency, etc. These functions make loop response testing simpler and more direct, and engineers can obtain the required parameters directly from the oscilloscope without additional calculations or processing.

• Easy to use and integrate: The interface of SpectrumView and MSO6 series oscilloscopes is intuitive and easy to use, allowing engineers to quickly get started and test. At the same time, these devices also support integration with other test equipment, making them easy to use in complex test environments.

Comparison of spectrum information obtained using FFT and spectrumview functions.

Left: Acquisition of a longer time domain waveform, right: Acquisition of a shorter time domain waveform (FFT, resulting in serious spectrum leakage)

The MSO6 series oscilloscope is a high-performance device suitable for loop response testing. It has low noise performance and spectrum view function, can accurately analyze analog and digital signals at the same time, and provides a variety of advanced measurement parameters. These features enable engineers to more accurately evaluate the stability and performance of the system.