A multisampling technique was introduced to the phase error detector of Conventional Digital Tanlocked Loop(C DTL). In this new technique a number of samples ( M ) were taken at nonuniform intervals within one peri...A multisampling technique was introduced to the phase error detector of Conventional Digital Tanlocked Loop(C DTL). In this new technique a number of samples ( M ) were taken at nonuniform intervals within one period of the input signal. The novel system is called Multisampling Digital Tanlocked loop(MS DTL). The simulated model on the computer shows that for M =4, the system has a faster locking speed and wider locking in range compared with C DTL.展开更多
Purpose: This study provides a simple protocol for validation of the gamma passing rates and to identify the optimum values of % dose and mm criteria for dose distributions measured with a detector array. Methods: We ...Purpose: This study provides a simple protocol for validation of the gamma passing rates and to identify the optimum values of % dose and mm criteria for dose distributions measured with a detector array. Methods: We chose ArcCHECK detector array to illustrate the concepts. We used plans with uniform or quasi-uniform dose distributions along the detector array for testing in the presence of dose errors. For testing sensitivity to spatial shift we employed a plan with approximately constant dose gradient along the axis of the instrument. Results: We identified a representative set of parameters which describe performance of a detector array. We determined the minimum gamma-index acceptance criteria allowing the passing rates to reach 100% in the absence of errors, and identified the minimum fully detectable errors for such criteria. For our baseline plans delivered to ArcCHECK, 100% passing rates were obtained for 1.5% dose criterion together with ±3% minimum error detectable at 100% rate, and for 1.5 mm criterion together with the minimum fully detectable error of ±3 mm. We inspected the impact of selected program options on the passing rates. Conclusions: The protocol we developed provides a simple method of commissioning-style analysis of a detector array without a need for analysis of a large number of clinical plans.展开更多
This paper presents a novel approach of M-ary baseband pulse amplitude modulated signal processing via a parameter-optimized nonlinear dynamic system. This nonlinear system usually shows the phenomenon of stochastic r...This paper presents a novel approach of M-ary baseband pulse amplitude modulated signal processing via a parameter-optimized nonlinear dynamic system. This nonlinear system usually shows the phenomenon of stochastic resonance by adding noise. To thoroughly discuss the signal processing performance of the nonlinear system, we tune the system parameters to obtain a nonlinear detector with optimal performance. For characterizing the output of the nonlinear system, the derivation of the probability of detection error is given by the system response speed and the probability density function of the nonlinear system output. By varying the noise intensity with fixed system parameters, the phenomenon of stochastic resonance is shown and by tuning the system parameters with fixed noise, the probability of detection error is minimized and the nonlinear system is optimized. The detection performance of the two cases is compared with the theoretical probability of detection error, which is validated by numerical simulation.展开更多
文摘A multisampling technique was introduced to the phase error detector of Conventional Digital Tanlocked Loop(C DTL). In this new technique a number of samples ( M ) were taken at nonuniform intervals within one period of the input signal. The novel system is called Multisampling Digital Tanlocked loop(MS DTL). The simulated model on the computer shows that for M =4, the system has a faster locking speed and wider locking in range compared with C DTL.
文摘Purpose: This study provides a simple protocol for validation of the gamma passing rates and to identify the optimum values of % dose and mm criteria for dose distributions measured with a detector array. Methods: We chose ArcCHECK detector array to illustrate the concepts. We used plans with uniform or quasi-uniform dose distributions along the detector array for testing in the presence of dose errors. For testing sensitivity to spatial shift we employed a plan with approximately constant dose gradient along the axis of the instrument. Results: We identified a representative set of parameters which describe performance of a detector array. We determined the minimum gamma-index acceptance criteria allowing the passing rates to reach 100% in the absence of errors, and identified the minimum fully detectable errors for such criteria. For our baseline plans delivered to ArcCHECK, 100% passing rates were obtained for 1.5% dose criterion together with ±3% minimum error detectable at 100% rate, and for 1.5 mm criterion together with the minimum fully detectable error of ±3 mm. We inspected the impact of selected program options on the passing rates. Conclusions: The protocol we developed provides a simple method of commissioning-style analysis of a detector array without a need for analysis of a large number of clinical plans.
基金Project supported by the National Natural Science Foundation of China (Grant No 60702022)
文摘This paper presents a novel approach of M-ary baseband pulse amplitude modulated signal processing via a parameter-optimized nonlinear dynamic system. This nonlinear system usually shows the phenomenon of stochastic resonance by adding noise. To thoroughly discuss the signal processing performance of the nonlinear system, we tune the system parameters to obtain a nonlinear detector with optimal performance. For characterizing the output of the nonlinear system, the derivation of the probability of detection error is given by the system response speed and the probability density function of the nonlinear system output. By varying the noise intensity with fixed system parameters, the phenomenon of stochastic resonance is shown and by tuning the system parameters with fixed noise, the probability of detection error is minimized and the nonlinear system is optimized. The detection performance of the two cases is compared with the theoretical probability of detection error, which is validated by numerical simulation.
