Home > Speakers >

Randy Yates

Randy has over four decades of experience as a DSP and embedded firmware developer across the defense and commercial sectors, notably, satellite and missile tracking systems at GTE Government Systems, power-line communications at Texas Instruments, mobile handsets at Ericsson/Sony Ericsson, and DirectTV satellite broadcast audio via Modulus Video/Motorola.

He holds a B.S. in Electrical Engineering and a B.A. in Mathematics from the University of South Florida.

In his spare time he enjoys playing his Yamaha C3 grand and has been pianist and organist for several churches over the past 30 years.

Improved Binary FSK Carrier Offset Tracking using Model-Based Parameter Estimation

Status: Not yet available - Stay tuned!

Frequency modulation and detection is known for its superior resistance to noise when the carrier-to-noise ratio is sufficiently high, particularly for wideband FM. Conversely, its performance in lower CNR environments is known to degrade quickly and acutely, especially when operating at or below the second threshold, ending finally in total noise capture.

This behavior can wreak havoc with digitally modulated FSK systems, for example, when attempting to estimate carrier offset frequency in an AFC loop, and especially with mobile systems in which fades or changing channel conditions can cause temporary drops in CNR.

This problem can be addressed by using linear, model-based parameter estimation to model the input to the carrier offset estimator, estimate the model parameters on each AFC input block, reconstruct the estimated signal from the model parameters, and compute the mean-square error between the estimated signal and actual signal. If the mean-square error exceeds a heuristically-determined threshold, then the input signal is deemed corrupt and not used to update the AFC loop, otherwise one of the estimated parameters is used to update the loop.

Key Learning Points

  1. Introduction to Frequency Modulation
  2. Use-case for FSK Communications:
    • Power Efficiency versus Other Modulations
    • Bandwidth Efficiency versus other modulations
    • Implementation Complexity
  3. Variations of FSK Modulation:
    • Continuous-Phase Frequency Shift Keying (CPFSK), AKA Sunde’s FSK ([1, p.381])
    • Minimum Shift Keying (MSK)
    • Gaussian Minimum Shift Keying (GMSK)
    • M-ary FSK (M > 2)
  4. Detection approaches and their effect on power efficiency
  5. Noise performance of FM modulation and detection
  6. Theory of linear, model-based parameter estimation:
    • definition
    • representing model
    • estimating model parameters
  7. Simulations

References

[1] S. Haykin, Communication Systems, fourth edition. Wiley, 2001.

Go to Session