Electromagnetic interference
Nik: In The Office, when Dwight bugs the mallard, it creates a static noise that Jim can hear on the phone or radio. That noise was very common in the 1990s and 2000s, but I never hear it now. What was it?
ChatGPT: The noise you're referring to, commonly heard in the 1990s and 2000s when a mobile phone was about to receive a call or text message near a speaker, is known as electromagnetic interference (EMI). This specific type of EMI is often called radio frequency interference (RFI) when related to radio frequency signals.
Mobile phones communicate with cell towers using radio frequency (RF) signals. When a mobile phone was about to receive a call or a message, it would increase its power output to establish a strong connection with the cell tower. This sudden burst of RF energy could be picked up by nearby speakers or other audio devices not adequately shielded against such interference. The speakers would then convert this RF energy into an audible noise, often described as a buzzing, beeping, or "dit-dit-dit" sound.
The reason this interference is less common now is due to several factors:
- Technology Shifts: Modern mobile phones use different technologies for communication (such as 4G LTE and 5G) that operate at different frequencies and with different protocols compared to the 2G (GSM) networks prevalent in the 1990s and 2000s. These newer technologies might not create interference in the same way or as frequently.
- Improved Shielding and Design: Both mobile phones and audio devices have improved in design and electromagnetic compatibility (EMC). Better shielding and filtering in speakers, amplifiers, and phones reduce the likelihood of such interference being picked up and converted into audible noise.
- Digital Signal Processing (DSP): Modern audio devices often use digital signal processing which can help to filter out or reduce the impact of RF interference before it becomes audible.
- Changes in Usage Patterns: With the prevalence of smartphones, the nature of notifications has changed. Many people now use silent or vibrate modes more frequently, and the continuous data connections (such as 3G, 4G, and 5G) maintain a more constant communication with cell towers, reducing the occurrence of sudden bursts of RF energy that caused the most noticeable interference.
The scene from The Office where Dwight's bugged mallard creates a static noise is a humorous nod to this once-common phenomenon.
'Fast forward to 65 seconds to hear a sample:'