International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A composite PCM/FM+FM/FM system combines the spectral efficiency of the analog system with the accuracy of a PCM system when needed for specific sensors and allows the direct transmission of binary computer words if necessary. A PCM/FM+FM/FM system combines the bit sequence with the modulated subcarriers at baseband and the resultant modulates the carrier. In the design of the composite system it is of importance to determine the impact of the subcarriers on the bit error rate of the bit sequence and to determine the degradation of the output signal-to-noise ratio of the subcarrier channels caused by the bit sequence.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / With recent developments in telemetry transmitter technologies, significantly greater DC to RF power efficiencies can be achieved. These new high efficiency transmitter designs may impact overall system design trade-offs by reducing the system size and weight requirements for batteries, heat sinks, and cabling. Furthermore, these fully DC isolated, next generation ARTM Tier 0, I and II enabled devices offer unique options to the platform designer in EMI/EMC control and system design. Advanced manufacturing techniques coupled with adaptive microprocessor control promises enhanced functionality, improved performance and reduced unit costs. The paper presents the performance of a new, high efficiency, telemetry transmitter topology and the possible system benefits involved with the application of this advanced transmitter technology within modern and legacy telemetry platforms. Specific sub-assembly circuit design techniques will be discussed and compared with prior design approaches.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / This paper describes the use of an efficient FPGA design flow, called Ogre, developed at BYU to design and implement PCM/FM demodulators. Ogre exploits the notion of reuse by taking advantage of a library of specially designed cores parameterized by XML metadata. A judicious choice of library cores, targeted to signal processing functions common to sampled data modulators and demodulators, reduces the design and test cycle time. We demonstrate this by using the tool to construct rapid prototypes of three different versions of FM demodulators and show that the bit error rate performance is comparable to demodulators on the market today.

ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / White Sands Missile Range is the largest overland test range in North America occupying over 3,200 square miles in Southern New Mexico and nearby territory. One of the most critical test elements at White Sand Missile Range is it's capabilities in the telemetry field. Much significant advancement in technology has given WSMR and the entire electronics world the ability to achieve new levels of data acquisition that were not achievable a decade ago. And as attention to our nation's defense is of high priority, White Sands Missile Range provides to highest levels of telemetry competence in the Western Hemisphere.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / This paper will discuss the performance of pulse code modulation (PCM)/frequency modulation (FM) during frequency selective fading. Frequency selective fading occurs when the attenuation in part of the frequency band of interest is much greater than in the rest of the band of interest. The frequency selective fading model used in this paper assumes that two paths with different delays exist between the transmitter and receiver (multipath). The two-path model was simulated in the laboratory and the effects of frequency selective fading on the radio frequency (RF) spectrum and on the waveforms at the output of the FM demodulator were measured. A mathematical model was also used to predict the effects of frequency selective fading. The predicted waveshapes are compared with the laboratory data. A simple demodulator which alleviates the effects of frequency selective fading on PCM/FM at moderate signal-to-noise ratios (SNRs) will be described. This demodulator is created by detuning the telemetry receiver by a frequency equal to approximately one-half of the intermediate frequency (IF) bandwidth and using the receiver’s amplitude modulation (AM) detector output rather than the FM detector output. The performance of this offset AM demodulator will be compared with the performance of an FM demodulator. Frequency selective fades measured in real-world environments will be also presented.

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 emission of the telemetry signal is required over minimum two different antennas to keep the telemetry link available during a maneuver of a flying object. If nothing is made at the transmitter side, the telemetry link can be fully lost as both signals may have an opposite phase. We here propose a simple solution based on delay diversity to solve this problem. The basic idea is to introduce a delay between both emitted signals to guarantee a non-destructive signal recombination. We then exploit the ability of the blind equalizer developed by ZDS for the PCM/FM modulation to correctly equalize this signal and to recover the initial data. This solution does not require any modification of the on-board and floor set-ups except the introduction of a delay line between both transmitting antennas. It also does not need any pilot sequence and is natively robust to multipath perturbations.

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / The bit rates of telemetry systems are increasing rapidly. Higher bit rates occupy more spectra and result in decreased link margin. The major signal parameters that affect the spectral occupancy and bit error probability (BEP) of binary pulse code modulation (PCM)/frequency modulation (FM) signals are the bit rate, code, premodulation filter, and peak deviation. The measured spectral occupancy is also affected by the spectrum analyzer (or other measurement equipment) settings. Additional parameters that affect the BEP include the receiver intermediate frequency (IF) filter, the FM demodulator, and the bit detector. This paper will present the effects of these parameters on the measured 99% and -60 dBc bandwidths and the BEP of binary PCM/FM telemetry signals. Normalized BEP and bandwidth curves will be presented.

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A typical PCM/FM system is designed for a peak to peak carrier deviation of 0.7 times the bit rate of the PCM data. This value of PCM data deviation has been shown to be optimum for both PCM/FM [1] and PCM/FM+FM/FM [2] systems. However, the optimum deviation of the carrier by the FM subcarrier for a PCM/FM+FM/FM system is dependent upon the specific subcarrier type and required subcarrier signal to noise ratio at the receiver output. This paper introduces a simple method to calculate the optimum deviation of the carrier by FM subcarriers for a PCM/FM+FM/FM system. The method developed is used to calculate the optimum value of subcarrier deviation for two sample PCM/FM+FM/FM systems when IRIG constant bandwidth channels are used as FM subcarriers. The calculated optimum values of FM subcarrier deviation of the carrier, subcarrier mod index, are utilized in a companion paper to study the performance of PCM/FM+FM/FM systems [3]. The work presented herein can be extended to calculate the optimum deviation of the carrier by FM subcarriers for any PCM/FM+FM/FM system.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Since the 1970s PCM/FM has been the dominant modulation scheme used for RF telemetry. However more stringent spectrum availability as well as increasing data rates means that more advanced transmission methods are required to keep pace with industry demands. ARTM Tier-I and Tier-II are examples of how the PCM/FM link can be enhanced. However these techniques require a significant increase in the complexity of the receiver/detector for optimal recovery. This paper focuses on a quantitative approach to improving the rate and quality of data using existing PCM/FM links. In particular ACRA CONTROL and BAE SYSTEMS set themselves the goal of revisiting the pre-modulation filter, diversity combiner and bit-sync. By implementing programmable adaptive hardware, it was possible to explore the various tradeoffs offered by modifying pulse shapes and spectral occupancy, inclusion of forward error correction and smart source selection. This papers looks at the improvements achieved at each phase of the evaluation.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper will provide an overview of the process used to develop the bandwidth efficient modulation sections of the Inter-Range Instrumentation Group (IRIG) standard. The modulation method selected was Feher’s patented quadrature phase shift keying (FQPSK-B). The important characteristics of a bandwidth efficient modulation method for aeronautical telemetry will be presented first followed by a summary of the results of the research, laboratory test, and flight test efforts. Future plans will then be summarized followed by the FQPSK-B sections of the current IRIG Telemetry Standard (the standard is available online at: http://tecnet0.jcte.jcs.mil/RCC/oldoc.htm).