MIL-HDBK-421 Base Document:1991

1 Scope
  1.1 Purpose
  1.2 Application
  1.3 Objective
2 Applicable documents
  2.1 Government documents
  2.2 Non-Government publications
  2.3 Order of precedence
3 Definitions
  3.1 Acronyms used in this handbook
  3.2 Accuracy
  3.3 Aging
  3.4 Alternate clock
  3.5 Ambiguity
  3.6 Calibration
  3.7 Closed-loop noise bandwidth
  3.8 External timing reference
  3.9 False lock
  3.10 Fractional frequency fluctuation
  3.11 Free-running capability
  3.12 Frequency difference
  3.13 Hold-in frequency range
  3.14 Independence of clock-error measurement and correction
  3.15 Independent clocks
  3.16 Information
  3.17 Limit cycle
  3.18 Local clock
  3.19 Long-term stability
  3.20 Loop filter
  3.21 Major node
  3.22 Minor node
  3.23 Nodal clock
  3.24 Nominal value
  3.25 Nonlinear phase
  3.26 Offset
  3.27 Offset frequency
  3.28 Overall accuracy
  3.29 Phase instability
  3.30 Phase microstepper
  3.31 Principal clock
  3.32 Pull-in frequency range
  3.33 Quartz clock
  3.34 Quartz oscillator
  3.35 Random clock errors
  3.36 Rubidium clock
  3.37 Rubidium standard
  3.38 Sampling
  3.39 Secondary time standard
  3.40 Signal transit time
  3.41 Spectral purity
  3.42 Stability
  3.43 Standard frequency
  3.44 Subservient clock
  3.45 Subservient oscillator
  3.46 Sweep acquisition
  3.47 Synchronous system
  3.48 Time ambiguity
  3.49 Time delay
  3.50 Time-division analog switching
  3.51 Time-division digital switching
  3.52 Time interval
  3.53 Time marker
  3.54 Time measurement tolerance
  3.55 Time-reference distribution correction
  3.56 Timing
  3.57 Timing ambiguity
  3.58 Timing reference
  3.59 Timing signal
  3.60 Tracking error
  3.61 Transit time
  3.62 Uniform time-scale
  3.63 Variable storage buffers
  3.64 Warm-up characteristics
4 General requirements
  4.1 General
  4.2 Frequency sources
  4.3 Data buffers
  4.4 Network internal timing methods
  4.5 Fundamental timing and synchronization approaches
       4.5.1 Master-slave
       4.5.2 Independent stable clocks
       4.5.3 Frequency averaging
       4.5.4 Pulse stuffing
       4.5.5 Time-dependent stable clocks
       4.5.6 Timing for networks requiring accurate time
5 Timing and synchronization fundamentals, concept, and
  related theory
  5.1 Jitter
       5.1.1 Sources of jitter
       5.1.2 Jitter tolerance
       5.1.3 Jitter measurements
       5.1.4 Jitter magnitude
       5.1.5 Maximum jitter
       5.1.6 Jitter threshold seconds
  5.2 Phase-locked loop
       5.2.1 Linear analysis of the phase-locked loop
       5.2.2 Phase detector
       5.2.3 Loop filter
       5.2.4 Voltage-controlled oscillator
  5.3 Phase-locked loop synchronization performance
       5.3.1 Frequency hold-in range
       5.3.2 Frequency pull-in range
       5.3.3 Acquisition time
       5.3.4 Fly-wheeling performance of synchronizing
             systems
       5.3.5 Threshold performance of synchronizing loops
       5.3.6 Optimum synchronization system
  5.4 Phase-locked loop performance in a multipath
       environment
  5.5 Timing accuracy for a pseudonoise sequence
       5.5.1 Basic approach
       5.5.2 The Jet Propulsion Laboratory's error detector
             for locking to a PN sequence
  5.6 A concept for disseminating precise timing throughout
       a communications network
       5.6.1 Basic concept
       5.6.2 Alternate solution
       5.6.3 Conclusion
  5.7 A synchronous timing system
       5.7.1 Background
  5.8 A time-dissemination and Doppler-canceling system for
       satellite access
       5.8.1 Introduction
       5.8.2 Concept description
  5.9 Quadrature phase-modulated synchronizing system
       5.9.1 Introduction
       5.9.2 Approach
       5.9.3 Example of an adaptive synchronous coherent
             detector for a quadrature phase-modulated
             system
  5.10 Timing errors
  5.11 Closed-form timing error equation
  5.12 Buffer size requirements
  5.13 A uniformly spaced frequency band generator
  5.14 A simple circuit for implementing a median frequency
       generator
6 Timing sources
  6.1 Common frequency standards
  6.2 Quartz crystal oscillators
  6.3 Rubidium frequency standard
  6.4 Cesium-beam frequency standard
  6.5 Hydrogen maser atomic clock
  6.6 Comparison of common timing sources
7 Example of time-dependent, timing, and time-dissemination
  systems
  7.1 Tactical network timing system
  7.2 Single channel ground and airborne radio system
  7.3 Satellite communications
  7.4 HAVE QUICK
  7.5 Joint Tactical Information Distribution System
  7.6 VERDIN
  7.7 TACAMO
  7.8 Other systems
  7.9 Time-dissemination systems
  7.10 Other dissemination means
  7.11 Other dissemination systems
8 Notes
  8.1 Subject term (key word) listing
Figures
Tables
Appendixes
A - Loran-C, Omega, and VLF Transmitting stations and Time
    signals emitted in UTC systems
B - Supplemental reading

Prepared to assist engineers and staff planners in understanding military communications timing and synchronization characteristics found in the timing and synchronization needs of the military communications environment.