Signal to Noise Ratio

Signal to noise ratio, or SNR, is the ratio of the power of a desired signal to the power of the noise.

SNR = Psignal / Pnoise

Signals are the desired content of the message. You send an SMS. You’re expecting an offer letter in your email. You’re listening to a speaker at a conference, and their voice is amplified through the audio system and their video is projected onto white screens.

Noise is the stuff that gets in the way of the intended message. In audio, we recognize noise as the hum in our speakers and headphones when no music is playing, which can sometimes be heard in quiet passages of the song. In online discussions, we identify noise as most YouTube comments. Noise goes by a lot of names. Fake news. Junk mail. Spam. Propaganda. Advertisements. Static. Interference. Bias.

In most respects, we want the SNR to be as high as possible. That is, we want to send strong signals and remove as much noise as we can. What does that look like?

  • Camping. Summer is the time to hit the trails and camp sites, and with Canada 150, access to National Parks is free. That means getting away from the city and turning off your phone (sometimes). That allows a person to clear the noise from their heads and reconnect to the quiet and important messages from their minds, bodies, souls, hearts.
  • My piano teacher taught me that if I want to play louder, I can either pound away on the keys and hurt my forearms or I can play my quiet passages quieter.
  • Wi-Fi. When you live in an apartment or condo, most people’s wireless is on the frequency band 2.4 GHz, and even the same channel within it, making it hard for devices to pick out your precise Wi-Fi network even if your signal is strong. Same with cordless phones, microwave ovens. A quick hack to boost your Wi-Fi reception is to choose a channel that no one else is on. That is, you reduce the noise by tuning it out.

That’s all well and good, but what even makes a good signal and what is considered noise? There’s a lot of good messages out there, so what’s a useful indicator to recognize signal vs noise? Eat your vegetables. Exercise 30 minutes every day. Drink water. Follow your dreams. Be a lover, not a fighter. Decent signals can have a high SNR. On the other hand, some people’s whole jobs and life missions is to amplify the noise to distract you from the signals you need to hear, using racism and xenophobia, sexism, trans- and homophobia, ableism, ageism, classism, all the -isms and izzles. Systems are put in place to keep you busy filtering out noise while the powers that be keep you oppressed and less likely to bother them.

One way to distinguish whether a signal is useful is its timeliness. When it’s received on time, when it’s needed or expected, that means it’s a good signal. It gets you unstuck. When I started blogging about The Struggle, a few people told me I should write about this particular topic or another one because it would be so important for people to hear. I declined all of those requests because truly, the most relevant topics came to me on their own every week. They weren’t ever really suggestions by others. It was merely a reflection of what my conflict was that week, and I’ve worked very hard to keep it that way. There are a lot of good topics I could explore, but the reason the writing can be so poignant for me is because of its timing. Certainly my topics won’t be timely for everyone every week, but choosing a message that isn’t relevant in its timing would decrease my SNR.

Reception. In order for a signal to reach you, you both have to be tuned to the same frequency. My friend got a tattoo this week. After several years of thinking about it, one particular artist in Calgary caught their attention. They could have gotten it at any time and any place, but once they knew what they wanted, finding the right person who was putting out the right signals made them lock on to that channel. The artist’s Instagram page is pretty consistently updated, but it’s hard to make a big splash when there’s so much noise. So many bots and spam accounts.

Filters. As in circuits, we can cut out the noise by setting up a passive filter. I stopped watching lectureporn like The Daily Show, Last Week Tonight, Samantha Bee, and when Carrie watches those shows, I ask if she can watch with headphones on. I do value being informed, but it drains me to keep up with all the political hobbyists when I have more pressing matters at hand. I can only enjoy feeds like Reddit and Twitter when I have my filters well-curated.

Patterns. I have to write to clear the noise out of my head every week. I noticed that was a pattern that helped me. Prior to The Struggle, I only really wrote every few weeks once something interested me or piqued my curiosity. Then I noticed how much better I felt once I made writing more regular. When I don’t write consistently, other parts of my system feel the strain and have to compensate. I snack more. I exercise less. I clench and grind my teeth. My upper back stiffens up and I get more knots tangled up in the muscle fibres. Regularity makes for a clear message. Having weekly coffees with coworkers. Making special time for your loved ones.

Searching for signal. One way of quieting the noise is by changing channels. For people familiar with any device with a radio, this analogy is quite literal. Old TVs had this. FM radio. You can remove the static by going to a different channel.

Pain is a huge signal. Sometimes it can be signal, sometimes it’s noise. Lifting weights, you should feel a resistance. That’s a good sign. When I felt a sharp searing pain, it was because I was using terrible technique for so long that a tendon or ligament was being pinched between bones when they weren’t supposed to be. Bad kind of pain. Signal that I’m doing something wrong.

Emotions are hard because they send us mixed signals. We tend to logically interpret our feelings as strictly binary, either yes or no, but all human relationships are murky because we can both love and hate a person to varying degrees depending on which side of them we’re looking at, including ourselves.

You’re probably thinking “Okay, Jon, we get it. We’re not dumb like you. Tell us then, what signals is your body sending to you?”

Great question. I’m getting a lot of signals right now. Let’s lay them all out on the table and examine them together. Working with so many people, I get reflections of myself through a lot of different ways.

  • Sleepy. I’ve never been so “on” for a job before. I feel alive and in the moment, and if I’m not well-rested, I perform suboptimally. I’m learning so much, and empathizing all day is new to me. My emotional muscles are getting a full workout, so I finish the day and just want to pass out. I’ve worked hard at other jobs before, but it’s an entirely different beast when you love what you’re doing.
  • I’m very hard on myself still. While I’ve worked a lot on being as compassionate to myself as I usually am to others, I beat myself up hard when I make a mistake. I’ll feel terrible, worry that someone is going to punish me, and curse myself a lot, loudly, creatively, and in a short period of time.
  • My physical posture is getting better, but it requires a lot of work. Still major knots in my traps. Hip flexors are loosening. Feet are much better thanks to the orthotics. My sore back is a pain in the ass. I’m done processing my childhood trauma emotionally, but I’m not done processing it physically yet. Even then, I can’t tell which of the three areas I should focus on and when. The only way I can tell is from which one is hurting the most at the time, which feels like an endless game of whack-a-mole.
  • Eating right. I eventually want to get around to this, but too much going on right now. I know that you can lose a ton of weight simply by eating better, but my resources are tied up right now with other tasks. Exercise is nowhere near as important as limiting calories, and I’m still eating my feelings.
  • I’m really forgetful. I used to memorize all my piano pieces, the tradeoff being that I was terrible at playing from sight reading. Since I stopped relying on those mental muscles, I pretty much have a goldfish memory. I’ll shampoo my hair in the shower, then I’ll rinse and repeat because I’ll already have forgotten if I shampooed my hair. I can’t say that I’ve blacked out much while overdrinking, which is weird considering how much I’ve binge-drunk before.
  • When I get nervous, I stop breathing. I need to consciously slow down and breathe so that I can get back into my groove.

Sometimes we don’t like the signals we’re hearing, so we crank up the noise. That is, we’re reducing the signal to noise ratio. We want to drown out that feeling. When my heart aches, I’ll put on some headphones and listen to some dubstep. Wub wub wub.

Power supply rejection ratio. PSRR. In electronic circuits, operational amplifiers can transmit the noise from the power supply into the output signal. PSRR is rated at how many decibels it can suppress at a particular frequency. For instance, power lines can pick up radio signals and general static. It’s up to the amplifier to filter out the noise to keep the power from entering into the signal. One example is that audible pulsating buzz in audio equipment when someone with a GSM phone makes or receives a phone call. In life, we see politicians being influenced by the money being donated by lobbyists. TV and radio shows alter their content depending on whether their sponsors and advertisers will like it.

What does power supply rejection ratio have to do with noise and relationships? It’s a topic I wrestled with regarding my parents. They would give me power, such as room and board, food, love, nurturing, access to education, a car, financial assistance. There would sometimes be strings attached to those gifts. Some of them were reasonable, like doing my chores, helping out around the house, driving things or people to places at certain times. Other obligations were not reasonable, like being taken advantage of, abused, manipulated, berated. The Asian parental mentality is often “I’ll take care of you when you’re young so that you can take care of me when I’m old,” so there’s this expected reciprocity. "Love" can often be given as a favour to be returned, not as a gift. As much as I appreciated the power they supplied me, I had to increasingly reject the growing noise they transmitted my way to the point where I had to remove myself from the channel entirely. I got a new power supply, a new family to support me.

Clear as mud? Signal good, noise bad. Sometimes signal bad, noise good. Filter signals and noise by squinting or changing tune. Power supply can introduce noise, so reject it or get a new one if it gets too loud.

Jonathan Phan Lê @jon_le