Signal transmission over large distances exposes systems to various environmental disturbances, causing attenuation, distortion, interference, and noise. Filters remove these unwanted signal components—maintaining the signal integrity and improving your system efficiency.
The choice of filter depends on the type of signal you’re dealing with. Knowing about the working of these filters will give you a clear understanding of their functions and benefits.
Here’s a list of differences between analog and digital filters that you should know about.
1. Working Signal
As the name suggests, analog signals deal with real-time signals while digital filters use the samples of continuous signals as their input.
2. Circuit Components
The combination of any circuit depends on its working and signals requirements—another reason why these filters use different circuit components. While analog filters can be implemented by using RLC components, digital filters require adders, delays, and subtractors.
3. Frequency Response
A measure of the output phase and magnitude as a function of frequency, it’s the representation of the system dynamics and represents how the output spectrum changes as a response to the applied stimulus. To achieve the desired response in analog filters, we require computation of the approximation problem whereas; we design special coefficients to meet the frequency criteria in digital signals.
4. Causal and Stable Response
The stability response of a system is determined by means of its transfer function G(s). For analog filters, the response is represented by the ratio of Laplace variables with real coefficients. Digital filters, on the other hand, use a ratio of z-transforms with real coefficients to represent their system response.
5. Environmental Changes
As analog filters work on continuous time signals, they’re prone to environmental changes which often cause distortion, attenuation, and interference. Since digital filters work on samples of the real-time signal, they’re less susceptible to environmental disturbances.
6. Flexibility
Digital signals offer design flexibility as they’re programmable and can be easily reprogrammed according to design requirements. This isn’t the case for analog filters—a design change requires redesigning of the entire circuit, a less feasible option as compared to digital filters.
7. Additive Noise
RLC components are prone to heating due to continuous current flow—a reason why analog filters suffer from thermal noise. Digital filters take samples of the signals at any given time interval, increasing the chances of quantization error or digital noise.
8. Design Benefits
The fact that there’s no need to write an operational algorithm for analog circuits makes their implementation easier. While digital filters require microprocessors and other controllers, they offer higher efficiency, filtering even the lowest frequencies.
Both of these designs have their own benefits and limitations. When it comes to choosing one for your system, pick one that matches your input requirements.
ADSANTEC provides high-efficiency digital filters at competitive rates to improve your system response and reduce the effect of noise and other disturbances. Our range of products includes Boolean logic gates, 4-bit ADC, clock dividers and signal generators, amplifiers, and multiplexers.