Analog vs Digital I/O
Why You Need to Know the Difference Between Analog vs Digital Input
Why do you need to bother distinguishing between the two input methods?
Frankly, the distinction is essential for circuits’ signal processing.
You should be aware of it to avoid improperly combining one system with another.
Additionally, analog input has quite different applications from digital input.
If you make a mistake, you will be in the wrong direction in two of the most essential elements of controlling industrial machinery:
The Distributed Control System (DCS) and Programmable Logic Controller (PLC) system.
Sensors like absolute sensors are used in conjunction with DCSs. The DCS aids in the production process by regulating the flow of materials through the plant.
Meanwhile, the Programmable Logic Controller controls the behavior of commercial equipment.
It gets signals (inputs) from buttons or switches, which are pressed by humans.
PLC then issues commands to the machines to carry out specific tasks as ordained by its programming.
DCS and PLC for digital and analog systems are not the same.
Analog Input Explained
Information enters a machine using analog inputs.
The term “analog input” is often referred to as Analog I/O in the field of IT and electronics.
To explain it easily, let’s take a person’s voice as an example.
The speech input for a recording device comes from an analog source (the voice), and the voice recorder (machine) processes this analog data.
Other types of analog inputs are:
- Animal/ human voice
- Atmospheric conditions/climate/weather
- Body temperature
- Human/animal movement
An interface is needed to accept information from these analog signals or analog inputs.
This interface is called an Analog Input Device. In our example with the human voice, this machine is the voice recorder.
Circuit Boards for Analog Input
Analog circuit boards require a different approach to noise management and routing than Digital PCBs do.
The issue is frequently current spikes that are exposed to analog PCBs.
Sometimes radio transmissions and other times power lines are the sources of EMI (otherwise referred to as “noise”).
To ensure flawless operation, the analog board’s frequency range must be adjusted properly.
Designing analog PCBs requires the use of a separate plane.
Even common digital planes should not contain sensitive components like amplifiers.
In addition, the power supply must be separated from the analog components because it can cause voltage spikes.
Digital Input Explained
You can read the data from the machine’s measurement interface thanks to a digital I/O device.
Let’s imagine that you enter a number into the ATM.
The computer translates the number so that it can give you money.
In this instance, the keypad, the ATM’s relay, is used to input the digital input.
Significantly, when we compare Digital I/O to Analog I/O, digital ones have the following advantage:
- Better allocation of power
- Optimized for Impedance Control
- improved resistance to EMI incidents
- keeps the signal’s original message intact.
- Lower noise generation
- Reduced interference between nearby channels.
Circuit Boards for Digital Input
Digital PCBs have more microchips and other high-performance board modules than analog PCBs do.
ICs and BGAs surface mounted on them enable them to process a few billion operations per second.
Using conductive traces etched on laminated copper and positioned between non-conductive substrate layers, a Digital PCB is a brilliant piece of work.
Digital PCBs manage and connect electrical components and are sold by reputable companies such as us, PCBMay.
Converting Analog Input to Digital Input
In this area, we’ll concentrate on the conversion of analog to digital signals. Why, then, is it significant?
We live in a world that is becoming more and more digital, so we need to convert analog signals to digital ones.
For instance, using the illustration of voice recording again, once we have recorded a person’s voice, we have digitalized it.
Then, we can use digital machines to amplify, reproduce and tweak the recording to our liking.
We can even distribute the voice recording as many times as we want.
Instead of the person repeatedly saying words, we can just use the digital version to save time and effort.
This problem can be resolved by analog-to-digital converters.
Analog-to-Digital Converters (ADC Converters)
The following ways are used by ADC converters to make an analog signal digital:
- Mapping values into sets so that the analog information becomes a set of values. Only the values inside the set are recognized by the digital system as a legitimate signal.
- Mapping values into discrete-time signals that only use independent variable’s integer values. This is necessary so that the computer memory can store the signals that were captured. Digital cable TV signal is a common example we can cite.
You can look at the illustration below to see the discrete-time and discrete-amplitude difference in analog and digital inputs:
Discrete-Time & Discrete-Amplitude
There are several ADC converters out there that you can use. The most common are:
- Direct Type or Flash ADC – much used in video digitalization
- Dual Slope
- High-Fidelity ADC (Sigma-Delta)
- SAR (Successive Approximation)
- Semi-flash ADC
Just remember that data collection is improved with the innovative usage of Integrated Circuits in ADC circuits.
The data is collected more quickly and with greater accuracy. High-performance ADCs have precise throughput and increased reliability + repeatability.
Another boost is cheaper price + lower power consumption.
Meanwhile, EMI noise susceptibility is lowered to make the use of ADCs very convenient.
If ever you need a circuit board for ADC, you can contact PCBMay for it.
What is Mixed Signal Input?
If a device has a mixed signal input, you’ll need an IC to accept two different types of signals.
There are two approaches to enable mixed signals: the first is the use of controllers. These consist of the ADC and DAC.
The CODEC hardware is the second means via which mixed signals are made viable.
CODEC hardware is specifically designed to transform signals from analog to digital data streams. It can also reverse the direction, transforming digital data streams to analog.
This type of hardware includes both ADC and DAC functionalities.
There are several types available in the market such as:
- IC Digital Video Decoder (Thin Quad Flat Pack)
- IC Encoder RGB to NTSC (System-on-a-chip)
- Signage video transmitter cards
Mixed Signal IC
Circuit Boards for Mixed Signal Input
ICs such as those named above are surface mounted on PCBs (circuit boards)
The following guidelines below must be adhered to while creating mixed signal PCBs:
- The priority is to reduce EMI and crosstalk noise issues
- Focus on cabling techniques, employ decoupling, or eliminate capacitance.
- For wiring purposes, capacitors are necessary for simulators; they must be connected close to the power pin.
- Separate the various types of digital circuitry from analog circuitry
- Stick to the PCB schematic, and if you have any doubts, you can use professional PCB design service providers.
- The pins must be maintained as short and as close to the power source as necessary.
- Proximity of the power source to the component it is powering must be taken into account in power integrity design
- At the same time, the power source must not be too close to sensitive components
- Your mixed signal PCB will succeed with correct coordination, especially on the surface wire and power cord.
PCB for Mixed Signals
Types of PCBs that can handle mixed signals are:
- Double-sided PCB – some simple appliances use this type
- Flexible PCB – these are common in miniaturized devices like smartwatches
- Hard Gold PCB – like those in the terminal edge of memory boards
- HDI PCB – for high-definition, wireless and internet application
- High-Frequency PCB – possibly used for automotive and advanced tools
- LED PCB – lighting and LED relays
- Multilayer PCB – above 4-layer to 40-layer PCBs
- Metal Core PCB – for high-heat resistance guarantee
- Rigid PCB – solid boards with no flex parts
- Rigid-Flex PCB – rigid boards with connectors attached to FPC
You may learn more about the differences between analog and digital inputs from our blog.
We had a lengthy discussion about analog signals.
Then, we discussed digital signage. Finally, we talked about mixed signals.
Electronic equipment is required for each of these signal input types.
These ICs are what are mounted on circuit boards later.
We are a PCB manufacturer based in China who can provide you with all types of circuit boards.
For over 12 years, we have handled PCB orders where analog inputs are required.
At the same time, we make OEM digital PCBs as well as mixed-signal ones.
Because you are a savvy PCB customer, you expect the best.
Your PCBs’ performance (analog, digital or mixed) shouldn’t cause you any concern.
For this reason, you must rely on a PCB manufacturer who has a solid reputation for ensuring customer satisfaction.
Please contact us right away so that we can finish designing your device.