Signal Analyzer Two-Pass Triggering for Unknown Transmissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Signal analyzers face significant processing demands when attempting to capture and analyze signal transmissions where neither the time nor the frequency is known in advance, as seen in sporadic transmissions from push-to-talk marine radios.
Innovation Solution
A two-pass triggering arrangement is employed, where the first pass locates the transmission of interest in frequency at the expense of time resolution, and the second pass determines the start time of the transmission, using a combination of time and frequency domain triggering criteria with tuners, spectrum calculators, and processors to efficiently identify and analyze the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the signal analyzer continuously monitors all frequency bands to capture unknown transmissions, then the probability of capturing a transmission is improved, but the processing demand and power consumption increase significantly
Solution Approach 1:
The frequency spectrum is divided into multiple bands, each monitored by a dedicated tuner. The processor selectively activates only the tuners corresponding to bands where transmissions are detected, rather than continuously processing all frequency bands. This segmentation reduces overall processing demand while maintaining comprehensive monitoring capability.
Solution Approach 2:
The system performs preliminary frequency-domain analysis using spectrum calculators to identify potential transmissions before initiating full-time domain analysis. This preliminary action filters out non-transmission signals, allowing the system to activate time-domain processing only when necessary, thereby reducing overall processing demand.
2Adaptability or versatility
If the signal analyzer uses wide frequency bandwidth to capture unknown transmissions, then the coverage of unknown frequencies is improved, but the time resolution and processing efficiency deteriorate
Solution Approach 1:
The wide frequency bandwidth is segmented into multiple narrower bands, each processed independently by dedicated tuners. This allows the system to maintain broad frequency coverage while processing each band with higher time resolution, as each narrower band can be analyzed more efficiently.
Solution Approach 2:
The system transitions from a single wide frequency-domain analysis to a multi-dimensional approach combining frequency-domain identification (using spectrum calculators) with time-domain analysis (using trigger generators). This dimensional separation allows frequency coverage and time resolution to be optimized independently in different processing stages.
3Loss of information
If the signal analyzer processes data from all frequency bands simultaneously, then the completeness of signal analysis is improved, but the processing time and system response speed deteriorate
Solution Approach 1:
The simultaneous processing of all frequency bands is segmented into parallel processing of individual bands by multiple independent tuners. Each tuner processes its assigned band independently, and the processor integrates results from active bands. This parallel segmentation maintains analysis completeness while significantly improving processing speed.
Solution Approach 2:
The system processes only the necessary frequency bands partially (selectively activating tuners based on detected transmissions) rather than fully processing all bands simultaneously. This partial action approach maintains sufficient analysis completeness for detected transmissions while reducing overall processing time and improving system response speed.
Data Source
AI summary
A signal analyzer comprises: a first tuner configured to tune to a first frequency band and to output first tuner data; a memory device configured to store the first tuner data; a spectrum calculator configured to calculate a series of spectra for the first tuner data; a processor configured to determine a presence of a transmission of interest within the first tuner data based on the series of spectra; a second tuner configured to receive the first tuner data stored in the memory device and to tune to a second frequency band including the transmission of interest. The second tuner outputs second tuner data in response to the stored first tuner data. The signal analyzer also comprises a transmission start time detector configured to receive the second tuner data and to determine a start time for the transmission of interest from the second tuner data.