The range of frequency generated by VHF oscillator is -
30 MHz - 300 MHz
Understanding the VHF Frequency Range
The question asks about the range of frequencies typically generated by a VHF oscillator. VHF stands for Very High Frequency. Radio frequencies are categorized into different bands, each with a specific range of frequencies.
What is Very High Frequency (VHF)?
Very High Frequency (VHF) is a radio frequency band defined by the International Telecommunication Union (ITU). This band is widely used for various applications, including radio broadcasting, television broadcasting, two-way land mobile radio systems (like police, fire, and ambulance), marine radio, amateur radio, and aircraft navigation and communication.
Frequency Bands Explained
Radio waves are generally divided into the following bands based on their frequency:
| Band | Abbreviation | Frequency Range |
|---|---|---|
| Low Frequency | LF | 30 kHz - 300 kHz |
| Medium Frequency | MF | 300 kHz - 3 MHz |
| High Frequency | HF | 3 MHz - 30 MHz |
| Very High Frequency | VHF | 30 MHz - 300 MHz |
| Ultra High Frequency | UHF | 300 MHz - 3 GHz |
| Super High Frequency | SHF | 3 GHz - 30 GHz |
| Extremely High Frequency | EHF | 30 GHz - 300 GHz |
Analyzing the Options for VHF Oscillator Frequency
An oscillator designed to operate in the VHF band will generate frequencies within that band's defined limits. Let's look at the given options:
- 300 MHz - 3 GHz: This range corresponds to the Ultra High Frequency (UHF) band, which is higher than VHF.
- Above 3 GHz: This range is part of the Super High Frequency (SHF) band and higher, also significantly above VHF.
- 30 MHz - 300 MHz: This range exactly matches the definition of the Very High Frequency (VHF) band.
- 20 kHz - 30 MHz: This range includes parts of the Low Frequency (LF), Medium Frequency (MF), and High Frequency (HF) bands, all of which are lower in frequency than VHF.
Based on the standard definition of the VHF frequency band, an oscillator designed to operate in this range will produce frequencies between 30 MHz and 300 MHz.
Conclusion on VHF Oscillator Frequency
Therefore, the range of frequency generated by a VHF oscillator is 30 MHz - 300 MHz.
Revision Table: Radio Frequency Bands
| Band | Frequency Range | Typical Wavelength Range |
|---|---|---|
| VLF (Very Low Frequency) | < 30 kHz | > 10 km |
| LF (Low Frequency) | 30 kHz – 300 kHz | 10 km – 1 km |
| MF (Medium Frequency) | 300 kHz – 3 MHz | 1 km – 100 m |
| HF (High Frequency) | 3 MHz – 30 MHz | 100 m – 10 m |
| VHF (Very High Frequency) | 30 MHz – 300 MHz | 10 m – 1 m |
| UHF (Ultra High Frequency) | 300 MHz – 3 GHz | 1 m – 10 cm |
| SHF (Super High Frequency) | 3 GHz – 30 GHz | 10 cm – 1 cm |
| EHF (Extremely High Frequency) | 30 GHz – 300 GHz | 1 cm – 1 mm |
Additional Information: VHF Oscillator Types and Applications
VHF oscillators are essential components in many electronic circuits that operate in the VHF spectrum. The type of oscillator used depends on the specific frequency stability and power requirements.
- Common VHF Oscillator Types: Crystal oscillators are often used for high stability at fixed VHF frequencies. For adjustable or wider frequency ranges, LC oscillators (like Colpitts or Hartley oscillators) or voltage-controlled oscillators (VCOs) are employed.
- Applications: VHF frequencies are suitable for relatively short-range communication (line-of-sight) and broadcasting. Examples include FM radio broadcasting (around 88-108 MHz), analog and digital TV broadcasting (in various VHF sub-bands), air traffic control communication, and marine communication.
- Wavelength: Frequencies in the VHF band correspond to wavelengths between 1 meter and 10 meters. This range allows for reasonably sized antennas, making VHF practical for mobile and portable devices.
Important Questions from Frequency Modulation
If f mis modulating frequency and m fis modulation index, then by the Carson's rule, the bandwidth of an FM signal at the input of a conventional discriminator will be:
The appropriate value of modulation index β for transition between narrow band and wide band FM is considered as:
Which of the following is NOT the advantage of frequency modulation ?
The modulation technique in which frequency of the carrier wave is changed with respect to the modulating wave is called:
What is the modulation index in a frequency modulated signal with a modulating frequency of 500 Hz and frequency deviation of 10 kHz?
