There is a lot to think about and prioritise in the hardware development process. However, one especially critical need that you will have if you are an engineer or startup overseeing such a project – whether you’re designing sophisticated audio equipment, telecommunications gear, or Internet of Things (IoT) devices – will be proving signal quality.
After all, if you are seeking to pitch your hardware to potential investors, partners, or clients, your hopes of success will largely hinge on your ability to provide clear and concise evidence of your hardware’s performance.
Well, the great news is that just one chart – a well-formulated frequency response plot – can be enough to showcase your system’s signal integrity with precision.
Why Signal Quality Is So Important
Signal quality is a measure of how clean and useful a signal is; it represents the ratio of the actual signal to unwanted noise and interference.
This means signal quality is of fundamental importance to the given hardware’s ability to fulfil its intended function. A clean signal ensures reliability, whether it is crystal-clear audio for a hi-fi brand, or robust data transmission for a 5G module.
The Power of a Single Frequency Response Chart
Certainly, the investors and clients making up the notoriously competitive tech scene in parts of the world such as the UK, will expect to see hard evidence of performance.
This is where a single well-crafted frequency response chart can be so powerful. Such a plot can demonstrate that the given hardware filters out noise effectively, preserves critical signals, and adheres to stringent industry standards.
A frequency response chart takes the form of a line graph illustrating how a given device handles different frequencies, showing amplitude against frequency. It serves as a “snapshot” of a system’s ability to pass desired signals and block unwanted ones.
For What Kinds of Hardware Would a Frequency Response Plot Be Relevant?
Let’s give a few examples of hardware projects that can benefit from the production of a single frequency response chart to be shown to parties like clients and investors:
- For an audio system, a chart can make it clear to observers how well the speaker system reproduces bass, midrange, and treble without distortion
- In the case of radio frequency (RF) communications systems, a chart can prove a device’s effectiveness at filtering out interference from nearby mobile or Wi-Fi signals
- As far as IoT sensors are concerned, a well-devised and clear chart can demonstrate that the given device ignores high-frequency noise while still accurately capturing low-frequency environmental data.
Low Pass vs High Pass Filters: Why Set a Cutoff?
Filters are a crucial element in the design of all manner of hardware products, given that they serve as gatekeepers of signal quality. By permitting certain frequencies to pass while attenuating (blocking) others, filters can ensure a focus on the signals that matter.
- Low-pass filters allow frequencies below a stipulated cutoff to pass, at the same time as blocking higher frequencies. So, they should be used when the signal of interest is low-frequency (as is the case with sub-bass in audio systems, for instance).
- High-pass filters are the direct opposite of low-pass filters – they permit frequencies above a certain cutoff to pass, but they reject lower ones. This makes them ideal for applications like RF communications, where it is necessary to eliminate low-frequency hum from power lines at the same time as preserving high-frequency data signals.
It can be a tricky balancing act to set a low-pass or high-pass cutoff for a given project. If you choose a cutoff for your hardware that is too near your signal’s frequency range, you risk attenuating the signal itself. Setting it too far away, though, could mean unwanted noise creeps through.
Fortunately, there are high-pass/low-pass filter calculators to be found online that can enable you to rapidly calculate cutoff frequency, as part of the all-round simplification of the design process.
How Can You Begin to Put Together a Pitch-Ready Frequency Response Chart?
Once you have designed the filter for your hardware, you will be able to measure the system’s frequency response, using a signal generator and oscilloscope or a spectrum analyser.
Then, you can get on with plotting the results in a clear and professional chart:
- X-axis: frequency (on a logarithmic scale, such as 20 Hz to 20 kHz for audio)
- Y-axis: amplitude (in dB or voltage)
- Highlight the cutoff: mark the 3 dB point to indicate where the filter kicks in
- Annotate important specifications: mention the cutoff frequency and the roll-off slope (for example, 20 dB/decade for a first-order RC filter).
You can generate these plots using tools such as MATLAB, Altium Designer, or even Excel.
Don’t Underestimate How Potent the Right Frequency Response Plot Can Be
All in all, a pitch-ready frequency response chart – particularly when backed by a well-designed filter – can play an instrumental role in your efforts to prove signal quality to prospective investors, clients, and other interested external parties.
This, in turn, can greatly help enhance the prospects of your hardware project in the fast-moving and demanding tech world.
