Frequency Bandwidth Calculator

Calculate frequency bandwidth, cutoff frequencies, and quality factor for RF systems

Calculate Frequency Bandwidth

Resonance frequency or geometric mean of cutoff frequencies

Measure of how underdamped the resonator is (unitless)

Bandwidth Analysis Results

0.000000
Frequency Bandwidth (MHz)
0.00
Quality Factor (Q)
0.000000
Center Frequency (MHz)
0.000000
Upper Cutoff (MHz)
0.000000
Lower Cutoff (MHz)

Formulas used: f_BW = f₀/Q = f_u - f_l, f₀ = √(f_u × f_l)

3dB point: Power is reduced to 50% (-3dB) at cutoff frequencies

Applications: Filter design, antenna systems, RF circuits, signal processing

Bandwidth Analysis

Example Calculation

FM Radio Station

Center frequency: 93.7 MHz

Quality factor: 500

Application: Radio broadcasting

Calculation

f_BW = f₀/Q = 93.7/500 = 0.1874 MHz

f_l = 93.6 MHz

f_u = 93.8 MHz

Bandwidth = 0.187 MHz

Frequency Band Applications

AM Radio10 kHz BW
FM Radio0.2 MHz BW
WiFi 2.4GHz22 MHz BW
LTE1.4-20 MHz BW
5G (low)600 MHz-1 GHz
5G (high)24-40 GHz

Key Concepts

3dB bandwidth: frequency range where power ≥ 50%

Higher Q = narrower bandwidth = more selective

Center frequency is geometric mean of cutoffs

Quality factor measures resonator sharpness

Understanding Frequency Bandwidth

What is Frequency Bandwidth?

Frequency bandwidth is the difference between the upper and lower frequencies in a continuous band that a system can process or transmit. It defines the range of frequencies where the system maintains effective signal transmission or reception.

3dB Bandwidth

  • Also called half-power bandwidth
  • Power drops to 50% at cutoff frequencies
  • -3dB corresponds to √2 voltage reduction
  • Standard reference for filter design

Key Formulas

fBW = f₀ / Q

fBW = fu - fl

f₀ = √(fu × fl)

  • fBW: Frequency bandwidth
  • f₀: Center frequency (resonance)
  • Q: Quality factor (dimensionless)
  • fu, fl: Upper and lower cutoff frequencies

Quality Factor: Q = f₀/fBW measures how "sharp" the resonance is

Applications and Use Cases

Communication Systems

  • • Radio and TV broadcasting
  • • Cellular networks (3G, 4G, 5G)
  • • WiFi and wireless LANs
  • • Satellite communications
  • • Bluetooth and IoT devices
  • • Amateur radio operations

Electronic Systems

  • • Filter design (low-pass, high-pass, band-pass)
  • • Amplifier frequency response
  • • Oscillator and resonator circuits
  • • Antenna design and matching
  • • Signal processing systems
  • • Medical imaging equipment

Design Considerations

Narrow Bandwidth (High Q):

  • Better selectivity and rejection
  • Lower noise bandwidth
  • Slower response time
  • More sensitive to temperature/component drift

Wide Bandwidth (Low Q):

  • Faster response and settling time
  • Better stability with variations
  • Higher data rates possible
  • Less selective, more noise