Passive Components Blog
No Result
View All Result
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    Advances in the Environmental Performance of Polymer Capacitors

    Vishay Releases DLA Tantalum Polymer Capacitors for Military and Aerospace

    Vishay Expanded Inductor Portfolio With More Than 2000 Stock Items 

    Paumanok Releases Capacitor Foils Market Report 2025-2030

    Modelithics Welcomes CapV as a Sponsoring MVP

    Wk 40 Electronics Supply Chain Digest

    Benefits of Tantalum Powder Stress–Strain Curve Evaluation vs Conventional Wet Test

    Electrolyte Selection and Performance in Supercapacitors

    Connector PCB Design Challenges

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Connector PCB Design Challenges

    Efficient Power Converters: Duty Cycle vs Conduction Losses

    Ripple Steering in Coupled Inductors: SEPIC Case

    SEPIC Converter with Coupled and Uncoupled Inductors

    Coupled Inductors in SEPIC versus Flyback Converters

    Non-Linear MLCC Class II Capacitor Measurements Challenges

    Percolation Phenomenon and Reliability of Molded Power Inductors in DC/DC converters

    Root Causes and Effects of DC Bias and AC in Ceramic Capacitors

    How to Calculate the Output Capacitor for a Switching Power Supply

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
  • Home
  • NewsFilter
    • All
    • Aerospace & Defence
    • Antenna
    • Applications
    • Automotive
    • Capacitors
    • Circuit Protection Devices
    • electro-mechanical news
    • Filters
    • Fuses
    • Inductors
    • Industrial
    • Integrated Passives
    • inter-connect news
    • Market & Supply Chain
    • Market Insights
    • Medical
    • Modelling and Simulation
    • New Materials & Supply
    • New Technologies
    • Non-linear Passives
    • Oscillators
    • Passive Sensors News
    • Resistors
    • RF & Microwave
    • Telecommunication
    • Weekly Digest

    Advances in the Environmental Performance of Polymer Capacitors

    Vishay Releases DLA Tantalum Polymer Capacitors for Military and Aerospace

    Vishay Expanded Inductor Portfolio With More Than 2000 Stock Items 

    Paumanok Releases Capacitor Foils Market Report 2025-2030

    Modelithics Welcomes CapV as a Sponsoring MVP

    Wk 40 Electronics Supply Chain Digest

    Benefits of Tantalum Powder Stress–Strain Curve Evaluation vs Conventional Wet Test

    Electrolyte Selection and Performance in Supercapacitors

    Connector PCB Design Challenges

    Trending Tags

    • Ripple Current
    • RF
    • Leakage Current
    • Tantalum vs Ceramic
    • Snubber
    • Low ESR
    • Feedthrough
    • Derating
    • Dielectric Constant
    • New Products
    • Market Reports
  • VideoFilter
    • All
    • Antenna videos
    • Capacitor videos
    • Circuit Protection Video
    • Filter videos
    • Fuse videos
    • Inductor videos
    • Inter-Connect Video
    • Non-linear passives videos
    • Oscillator videos
    • Passive sensors videos
    • Resistor videos

    Connector PCB Design Challenges

    Efficient Power Converters: Duty Cycle vs Conduction Losses

    Ripple Steering in Coupled Inductors: SEPIC Case

    SEPIC Converter with Coupled and Uncoupled Inductors

    Coupled Inductors in SEPIC versus Flyback Converters

    Non-Linear MLCC Class II Capacitor Measurements Challenges

    Percolation Phenomenon and Reliability of Molded Power Inductors in DC/DC converters

    Root Causes and Effects of DC Bias and AC in Ceramic Capacitors

    How to Calculate the Output Capacitor for a Switching Power Supply

    Trending Tags

    • Capacitors explained
    • Inductors explained
    • Resistors explained
    • Filters explained
    • Application Video Guidelines
    • EMC
    • New Products
    • Ripple Current
    • Simulation
    • Tantalum vs Ceramic
  • Knowledge Blog
  • Suppliers
    • Who is Who
  • Events
No Result
View All Result
Passive Components Blog
No Result
View All Result

Filter Bandwidth Explained

4.1.2023
Reading Time: 5 mins read
A A

This blog article from Knowles Precision Devices perform a deep dive on what bandwidth is and why we need to consider bandwidth when selecting a filter. 

In previous article, we provided a brief overview of five key filter specifications to understand, one of which was bandwidth. In this post, we will dive deeper into bandwidth by looking at the history of bandwidth, how bandwidth dictates data rate, and why the type of filter required will vary depending on an application’s bandwidth requirements.

RelatedPosts

Knowles Releases High Q Non-Magnetic X7R MLCCs for Medical Imaging

Knowles Unveils High-Performance Safety-Certified MLCC Capacitors

Knowles Releases Inductors for Mission-Critical RF Applications

First, let’s look at why bandwidth is important. In general, bandwidth is defined as the width of the passband of the bandpass filter and expressed as the frequency difference between the lower and upper 3 dB points. Bandwidth will dictate the data rate, or how quickly we can send information through a channel such as an optical fiber or a section of the radio spectrum.

A Historical Review of How to Calculate Bandwidth

To better understand bandwidth, let’s look back at some of the historical work that laid the foundation for how to consider this specification. In the 1920s, when Harry Nyquist was working on the telegraph at AT&T’s Department of Development and Research, the notion of the Nyquist Rate emerged from his work. In short, this is the theoretical minimum system bandwidth needed to detect Rs symbols per second is Rs/2 hertz.

A way to look at this more simply is to think about how signals behave in time when they are band limited. A signal such as a series of pulses that is band limited in the frequency domain gets distorted and smeared out in time. To stop these smeared-out pulses from overlapping and becoming indistinguishable at a detector, there needs to be enough bandwidth to contain all, or at least the majority, of the frequency components that make up that signal pulse. It turns out, the amount of bandwidth we need gives us the Nyquist Rate, which says that for things to make sense at the other end of a transmission, we can send pulses as fast as twice the channel bandwidth, but no faster.

Similarly, to understand why bandwidth follows when we need to increase data rate, let’s look at the Shannon-Hartley theorem that was developed in 1948 by Claude Shannon and Ralph Hartley, both researchers at Bell Labs. This theorem tells us that the maximum amount of error-free digital data that can be transmitted over a channel of a given bandwidth in the presence of noise, which is calculated using the following equation:

where:

  • C = Channel capacity in bits/second
  • M = Number of channels (e.g. the MIMO order)
  • B = Bandwidth in hertz
  • S = transmit power, in watts
  • N = noise on channel, in watts
  • S/N = signal to noise ratio

To increase channel capacity (data rates) we can increase bandwidth, the number of channels, or transmit power (S) or decrease the noise on the channel (N). Since this post is focused on bandwidth, we won’t get into too much detail about this, but it is worth noting that you can reduce N and increase channel capacity with filtering. For example, by including a filter with very low insertion loss, you could improve the overall noise figure, or you could address any aliasing effects that would bring out of band noise in the band of interest using a really good filter. 

How Does an Application’s Bandwidth Requirements Impact Filter Selection?

Bandwidth requirements vary widely by application as shown in Figure 1.

Figure 1. The relationship between bandwidth and frequency for a variety of common microwave systems adapted From: Demmin, Booz Allen Hamilton 68th IEEE Electronic Components and Technology Conference.

Since different applications require different data rates to successfully transmit signals without introducing noise, different types of filters are necessary as bandwidth and frequency increase. In short, the type of filter you need depends on where you are on the frequency versus bandwidth plot. More specifically, if you look back to Five Key Filter Specifications again, we also noted that we can look at the relative, or fractional, bandwidth of the filter. This is the ratio of a filter’s bandwidth to its center frequency. As shown in Figure 2, different filter technologies are capable of different fractional bandwidths.

Figure 2. Fractional bandwidths across frequencies for a variety of filter types.

Throughout this post, we looked at several different aspects of bandwidth, including how bandwidth is driven by the required channel capacity, or data rate; how different systems have different data rates, and hence, different bandwidths; and how different filter technologies are used to meet these varying bandwidth needs. In the next post in this series, we will spend more time exploring poles and zeros and how these are tools a filter designer can manipulate to improve a filter’s response.

Related

Recent Posts

Advances in the Environmental Performance of Polymer Capacitors

8.10.2025
2

Benefits of Tantalum Powder Stress–Strain Curve Evaluation vs Conventional Wet Test

3.10.2025
20

Electrolyte Selection and Performance in Supercapacitors

3.10.2025
16

Connector PCB Design Challenges

3.10.2025
20

Researchers Demonstrated High Energy Ceramic Capacitors Stable in Wide Temperature Range

2.10.2025
24

How to Manage Supercapacitors Leakage Current and Self Discharge 

1.10.2025
39

Experimental Evaluation of Wear Failures in SMD Inductors

1.10.2025
36

Resonant Capacitors in High-Power Resonant Circuits

1.10.2025
37
a Schematic diagram of the BNT-based components constructed based on the entropy-increase strategy. b Digital photograph, cross-sectional SEM image, and EDS mappings of the MLCCs. c Unipolar P-E loops of MLCCs as a function of applied E. d Wrec and η of the MLCCs as a function of applied E. The comparison of (e) Wrec and η, (f) η and UF of the MLCCs with those of other recently reported state-of-the-art MLCCs. source: Nature Communications

Researchers Proposed Enhanced Energy Storage MLCC

1.10.2025
18

Improving SMPS Performance with Thermal Interface Material

30.9.2025
12

Upcoming Events

Oct 14
16:00 - 17:00 CEST

Smart Sensors, Smarter AI: Building Reliable Edge Systems

Oct 17
12:00 - 14:00 EDT

External Visual Inspection per MIL-STD-883 TM 2009

Oct 20
October 20 - October 23

Digital WE Days 2025 – Virtual Conference

Oct 21
October 21 @ 12:00 - October 23 @ 14:15 EDT

Space and Military Standards for Hybrids and RF Microwave Modules

Oct 28
8:00 - 15:00 CET

Power Up Your Design: SN6507 and the Ready-to-Use Development Kit

View Calendar

Popular Posts

  • Buck Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Boost Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Flyback Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • LLC Resonant Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • SEPIC Converter Design and Calculation

    0 shares
    Share 0 Tweet 0
  • Dual Active Bridge (DAB) Topology Explained

    0 shares
    Share 0 Tweet 0
  • Ripple Current and its Effects on the Performance of Capacitors

    3 shares
    Share 3 Tweet 0
  • What is a Dielectric Constant and DF of Plastic Materials?

    4 shares
    Share 4 Tweet 0
  • Flying Capacitors Explained

    0 shares
    Share 0 Tweet 0
  • MLCC and Ceramic Capacitors

    0 shares
    Share 0 Tweet 0

Newsletter Subscription

 

Passive Components Blog

© EPCI - Leading Passive Components Educational and Information Site

  • Home
  • Privacy Policy
  • EPCI Membership & Advertisement
  • About

No Result
View All Result
  • Home
  • Knowledge Blog
  • Premium Suppliers

© EPCI - Leading Passive Components Educational and Information Site

This website uses cookies. By continuing to use this website you are giving consent to cookies being used. Visit our Privacy and Cookie Policy.
Go to mobile version