In this chapter, the operating principles of IFM receivers, some trade-offs in the designs, and several schemes for digitizing the outputs of the video amplitude will be discussed. Since an IFM receiver can measure only one input signal at a time, one continuous-wave (CW) signal will block the receiver from measuring other input signals. This CW problem will be discussed. The overlapping signal problem and some schemes to detect the existence of overlapping signals will also be discussed.

Chapter Contents:

• 6.1. Introduction
• 6.2. Principle of Operation
• 6.3. Basic Components in an IFM Receiver
• 6.4. Limiting Amplifiers
• 6.5. Power Dividers
• 6.6. Delay Lines
• 6.7. IFM Receiver with Multiple Correlators
• 6.8. Frequency Digitizing Window
• 6.9. Frequency Measurement through Amplitude Comparison
• 6.10. Frequency Measurement through Resistance Ring
• 6.11. Frequency Digitizing through A/D Converters
• 6.12. Pulse on CW Signal Condition
• 6.13. Simultaneous Signal Problems
• 6.14. Overlapping Signals Problems
• 6.15. Possible Solutions to Simultaneous/Overlapping Signal Problems
• 6.16. Simultaneous Signal Detection through Intermodulation Effect
• 6.17. Detection of Overlapping Signals
• 6.18. Differentiator Detection Scheme for Detecting Overlapping Signals
• 6.19. Sample/Hold and Compare Scheme for Detecting Overlapping Signals
• 6.20. Delay and Compare Scheme for Detecting Overlapping Pulses
• 6.21. Digital Detection Scheme for Overlapping Pulses
• 6.22. Resampling the Frequency Information
• 6.23. Summary
• References

Inspec keywords: frequency measurement; signal detection; radio receivers

Other keywords: CW problem; IFM receivers; video amplitude; instantaneous frequency measurement; overlapping signal problem; continuous-wave signal

Subjects: Signal detection; Radio links and equipment; Frequency measurement