6 Questions
Explain how the FM system works in RF telemetry applications.
In an FM system used for RF telemetry applications, the output of each transducer modulates the frequency of a voltage-controlled subcarrier oscillator. Multiple oscillators are mixed for radio transmission. At the receiving station, an FM modulator (discriminator) is used, which senses frequency variations and converts them into an appropriate voltage. The output of the discriminator is calibrated into a display of 01 to 30001.
True or false: The FM system described in the text is used for audio broadcasting applications.
False
What is the central frequency of the VCO in the FM system?
The VCO operates at a central frequency of 400 Hz, and it deviates +7.5% from the central frequency. The output of the VCO varies between 370 Hz and 430 Hz.
True or false: The VCO in the FM system has a frequency range of 370 Hz to 430 Hz.
True
How can the FM system be used to indicate the liquid level in a tank located far away?
The FM system can be used to indicate the liquid level in a tank located far away by using a transducer to measure the level and modulating the frequency of the VCO accordingly. The discriminator at the receiving station converts the frequency variations into an appropriate voltage, which is then calibrated into a display of 01 to 30001. This display can be used to indicate the liquid level in the tank.
True or false: The discriminator in the FM system converts voltage variations into appropriate frequency.
False
Study Notes
- An FM system is used for RF telemetry applications.
- The output of each transducer modulates the frequency of a voltage-controlled subcarrier oscillator.
- Multiple oscillators are mixed for radio transmission.
- FM modulator (discriminator) is used at the receiving station.
- The discriminator output voltage changes as the measurement value changes.
- The VCO operates at a central frequency of 400 Hz and deviates +7.5% from the central frequency.
- The output of VCO varies between 370 Hz and 430 Hz.
- The discriminator senses frequency variations and converts them into appropriate voltage.
- The output of the discriminator is calibrated into a display of 01 to 30001.
- This system can be used to indicate the liquid level in a tank located far away.
Test your knowledge on FM telemetry systems and their components with this quiz. Learn about how transducers modulate subcarrier oscillators and how FM modulators at receiving stations convert frequency variations into voltage. See if you can identify the central frequency and frequency deviation of a VCO and understand how a discriminator converts frequency variations into a display of liquid levels in a tank. Sharpen your skills on this important technology for RF telemetry applications.
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