International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Modem microcomputers are proving to be viable hosts for telemetry functions, including data simulators. A specialized high-performance hardware architecture for generating and processing simulator data can be implemented on an add-in card for the microcomputer. Support software implemented on the host provides a simple, high-quality human interface with a high degree of user programmability. Based on this strategy, the Physical Science Laboratory at New Mexico State University (PSL) is developing a Programmable PCM Data Simulator for microcomputer hosts. Specifications and hardware/software architectures for PSL’s Programmable PCM Data Simulator are discussed, as well as its interactive user interface.

International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The new generation of advanced tactical aircraft and missiles places unique demands on the electronic and mechanical designs for flight test instrumentation, high bit rates, operating temperature range and system interconnect wiring requirements. This paper describes a microminiature PCM distributed data acquisition system with integral signal conditioning (MMSC) which has been used in advanced aircraft and missile flight testing. The MMSC system is constructed from microminiature, stackable modules which allow the user to reconfigure the system as the requirements change. A second system is also described which uses the same circuitry in hermetic hybrid packages on plug-in circuit boards.

Item response theory models (IRT) are increasingly becoming established in social science research, particularly in the analysis of performance or attitudinal data in psychology, education, medicine, marketing and other fields where testing is relevant. We propose the R package eRm (extended Rasch modeling) for computing Rasch models and several extensions. A main characteristic of some IRT models, the Rasch model being the most prominent, concerns the separation of two kinds of parameters, one that describes qualities of the subject under investigation, and the other relates to qualities of the situation under which the response of a subject is observed. Using conditional maximum likelihood (CML) estimation both types of parameters may be estimated independently from each other. IRT models are well suited to cope with dichotomous and polytomous responses, where the response categories may be unordered as well as ordered. The incorporation of linear structures allows for modeling the effects of covariates and enables the analysis of repeated categorical measurements. The eRm package fits the following models: the Rasch model, the rating scale model (RSM), and the partial credit model (PCM) as well as linear reparameterizations through covariate structures like the linear logistic test model (LLTM), the linear rating scale model (LRSM), and the linear partial credit model (LPCM). We use an unitary, efficient CML approach to estimate the item parameters and their standard errors. Graphical and numeric tools for assessing goodness-of-fit are provided. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Binary PCM/FM has been widely adopted as a standard by the telemetry community. It offers a reasonable balance between detection efficiency and spectral efficiency, with very simple implementation in both the transmitter and receiver. Current technology, however, allows practical implementations of more sophisticated demodulators, which can substantially improve the detection efficiency of the waveform, with no changes to the modulator. This is accomplished by exploiting the memory inherent in the phase continuity of the waveform. This paper describes the implementation and performance of a noncoherent multi-symbol demodulator for PCM/FM. Sensitivity to offsets in carrier frequency, timing, and modulation index is also examined. Simulation results are presented which demonstrate improvements in detection efficiency of approximately 2.5 dB over traditional noncoherent single symbol detectors.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / There are two misty understandings about PCM telemetry system in conventional concept: Waveform can not be restored accurately; to be restored accurately, a measured signal must be sampled at a higher sample rate. This paper discusses that by making use of multi-sample rate DSP technology, the sample rate of a measured signal can be reduced in transmission equipment, or system precision can be retained even if the performance of low pass filter declined.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Transducers have traditionally been incorporated into data systems by connecting the transducer to a signal conditioner that is then connected to a multiplexer with an Analog-to-Digital Converter (ADC). The signal conditioning, multiplexer and the ADC are usually included within the same assembly that is called a Data Acquisition Unit (DAU) or an encoder. A network centric data system allows the same architecture to be used if the interface to the encoder is changed to be a network interface. However, a network centric architecture allows other options as well. The signal conditioning and ADC can be included within the same package as the transducer and the assembly can be interfaced to the network. When this is combined with the processing capability now available, a whole new range of possibilities present themselves. The transducer can now be digitally processed to provide a linear output, it can be converted to Engineering Units, digitally filtered or have a host of other functions performed within the housing that contains the transducer. However, the network centric approach does not produce these advantages without some disadvantages. The major problem that needs to be solved is how we time stamp the data. With the encoder we could time stamp the PCM frame and be able to determine the time that a sample was taken from that information. Even in systems that convert the encoder to have a network interface, the time stamp needs to be affixed to the data in the encoder. With a network centric approach, the sample can be taken in the transducer and how to time stamp it becomes a real problem. This is a problem that must be considered at the system level. Some method of making time available at a low enough level in the system to allow transducer outputs to be time stamped is either a network issue or it requires a separate interface.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / It has been shown that a multi-symbol detector can improve the detection efficiency of PCM/FM by 3 dB when compared to traditional methods without any change to the transmitted waveform. Although this is a significant breakthrough, further improvements are possible with the addition of Forward Error Correction (FEC). Systematic redundancy can be added by encoding the source data prior to the modulation process, thereby allowing channel errors to be corrected using a decoding circuit. Better detection efficiency translates into additional link margin that can be used to extend the operating range, support higher data throughput, or significantly improve the quality of the received data. This paper investigates the detection efficiency that can be achieved using a multisymbol detector and turbo product coding. The results show that this combination can improve the detection performance by nearly 9 dB relative to conventional PCM/FM systems. The increase in link margin is gained at the expense of a small increase in bandwidth and the additional complexity of the encoding and decoding circuitry.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Advancing technology continually generates larger quantities of data at increasingly high transfer rates which fuels the need for instrumentation to take up the challenge of efficiently managing the collection of data. This defines the driving force behind the desire for increased channel capacity of PCM data formatters. By incorporating state-of-the-art Digital Signal Processing (DSP) technology coupled with high-performance Field Programmable Gate Arrays (FPGA), Inter-Coastal Electronics has designed the IF-810, a PCM data formatter. The IF-810 allows eight channels of PCM data, one voice channel and an InterRange Instrumentation Group (IRIG)-B channel to be combined and formatted for recording onto the TEAC RX-800 series recorders using a Hi8 8mm video cassette as the recording media. During playback, the IF-810 clocks the PCM data out using a reconstructed version of the input clock. With this unique design, the PCM data and clock outputs are input directly to a decommutator which eliminates the need for costly bit-synchronizers. This paper discusses the integration of the DSP, FPGA and buffering techniques into a low-cost and efficient multi-channel PCM data formatter that accommodates high data rate inputs, all without the need of a bit-synchronizer for decommutation.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / It has been previously shown, through computer simulations, that a multiple symbol detector can provide substantial gains in detection efficiency (nearly 3 dB) over traditional PCM/FM detectors. This is accomplished by performing correlations over multiple symbol intervals to take advantage of the memory inherent in the continuous phase PCM/FM signal. This paper presents measured hardware results, from a prototype developed for the Advanced Range Telemetry (ARTM) Project, that substantiate the previously published performance and sensitivity predictions. Furthermore, this work confirms the feasibility of applying this technology to high-speed commercial and military telemetry applications.

ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / The performance of telemetry systems may be strongly affected by diverse sources of perturbations. Among them, multipath channels and transmission noise are the most critical. While the effects due to the multipath channels can be attenuated thanks to equalization, the effects of the noise are limited if forward error correction is used. This paper first proves that the combination of blind equalization and forward error correction can strongly improve bit error rates. The other objective of the paper is to show that reasonably powerful codes like Reed-Solomon codes are sufficient to enable quasi-error free transmissions in a large majority of propagation channel scenarios.