Oscilloscope PSD Measurement via 12-bit ADC and Algorithmic Processing
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Solution Overview
Problem
Current test and measurement instruments, such as oscilloscopes, are inadequate for performing power spectral density (PSD) and power level measurements required for 10GBASE-T applications, necessitating the use of multiple instruments and complex procedures.
Innovation Solution
An oscilloscope equipped with processing circuitry that algorithmically derives PSD from spectral data and plots it along with limit values, enabling single-instrument measurements comparable to those of a spectrum analyzer, using formulas like PSD=20*log 10(Z)−50+1.05 and Power (in dBm)=10*log 10(linear)+1.05, and employing MATLAB algorithms for data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single oscilloscope is used for PSD measurements, then device complexity and cost are reduced, but measurement precision was previously insufficient due to 8-bit A/D converter limitations
Solution Approach 1:
The patent changes the bit depth parameter from 8-bit to 12-bit A/D conversion, increasing the dynamic range from 48 dB to 72 dB. This parameter change enables the oscilloscope to achieve the required -117 dBm/Hz mask level measurement capability without requiring a spectrum analyzer, thus resolving the contradiction between using a single instrument and maintaining measurement precision.
2Ease of operation
If algorithmic PSD derivation is implemented in the oscilloscope, then ease of operation is improved by enabling single-instrument measurements, but device complexity increases due to additional processing circuitry
Solution Approach 1:
The patent merges the PSD measurement functionality into the oscilloscope by integrating algorithmic processing circuitry that derives PSD from spectral data. This combination allows the oscilloscope to perform both time-domain and frequency-domain measurements with a single instrument, improving ease of operation while the integrated design minimizes the added complexity compared to using separate instruments.
Solution Approach 2:
The patent replaces the need for mechanical/manual PSD measurement procedures with automated algorithmic processing. The processing circuitry automatically derives PSD from spectral data using mathematical algorithms, eliminating the need for manual operations and complex external equipment, thus improving ease of operation with manageable electronic complexity.
3Measurement precision
If 12-bit A/D conversion is used instead of 8-bit, then measurement precision is improved with 72 dB dynamic range, but use of energy increases
Solution Approach 1:
The patent changes the A/D converter resolution parameter from 8-bit to 12-bit, which increases the dynamic range to 72 dB and enables accurate measurement of the -117 dBm/Hz mask level. While this parameter change does increase energy consumption, it is a necessary trade-off to achieve the required measurement precision for 10GBASE-T applications using a single oscilloscope instrument.
Data Source
AI summary
A system and method for performing power spectral density (PSD) and power level measurements for measuring PSD required by 10GBaseT applications, using a single test and measurement instrument, such as a real time oscilloscope is described. That is, an oscilloscope includes processing circuitry which receives an input signal and converts it to raw data, it then transforms the raw data into specific analyzed displayable data by algorithmically deriving PSD from spectral data and plotting the PSD data along with limit values on a display screen of the oscilloscope.