Discovered a new favorite EE term thanks to Analog Devices - Page 1
Forum section: electronics / general

author: ZGoode
author_rank: Frequent Contributor
timestamp: April 03, 2025, 04:41:04 pm
content: I can always count on AD or TI to have weird language in their datasheets. Todays word that I now need to find a use for in a report at the lab is "squegging"credit to Kevin Santo Cappuccio on Twitter for making me aware of this amazing terminologyStraight from the datasheet of the LTC3108:Quote

author: tggzzz
author_rank: Super Contributor
timestamp: April 03, 2025, 04:52:24 pm
content: See also "motorboating".

author: PartialDischarge
author_rank: Super Contributor
timestamp: April 03, 2025, 04:54:18 pm
content: "Kinks" in optical devices is another interesting one

author: D2236
author_rank: Regular Contributor
timestamp: April 03, 2025, 04:55:36 pm
content: You will find "squegging" often mentioned in older books dealing with RF oscillator design.

author: TimFox
author_rank: Super Contributor
timestamp: April 03, 2025, 05:17:44 pm
content: "Squegging" is a well-defined term found in detailed analysis of oscillator circuits.It refers to an unwanted low-frequency almost periodic variation of the oscillator output due to a relaxation oscillation of the bias network, and requires a re-design of the coupling capacitor-bias resistor network.The word was not invented during your lifetime by Analog Devices, and the condition still exists.Even AI knows about it:https://rfcafe.com/references/ai/electronics-technology-principles/squeg-squegging-ai.htmA related article concentrating on squegging in RF MOSFET applications has several interesting references dating back to the 1920s:https://www.highfrequencyelectronics.com/Archives/Nov13/1311_HFE_squegging.pdf

author: Xena E
author_rank: Frequent Contributor
timestamp: April 03, 2025, 07:26:44 pm
content: Designed in squegging is used in self quenched super regenerative rf amplifiers to provide high gain where the integrated output oscillatory envelope is used as a greatly increased aproximate facsimile of the circuit input. Correctly designed they can reach noise floor levels of amplification.X

author: RoGeorge
author_rank: Super Contributor
timestamp: April 03, 2025, 08:01:20 pm
content: I didn't meet/notice the term before, but it seems to be a dedicated one, mentioned in the IEEE dictionary:QuoteQuoted text is from the "IEEE 100, the authoritative dictionary of IEEE standards, 2000".

author: TimFox
author_rank: Super Contributor
timestamp: April 03, 2025, 08:16:10 pm
content: Quote from: tggzzz on April 03, 2025, 04:52:24 pmSquegging and motorboating are related concepts.Usually, squegging is a feature of oscillators (wanted or unwanted), while motorboating is a feature of power distribution to a chain of amplifiers.Squegging can be used for some applications, but motorboating is not a good thing.(Motorboating is an example of onomatopoeia.)Here is a nasty example of unwanted squegging in an oscillator (roughly 3 MHz):Edit: correct oscillator frequency.

author: Analog Kid
author_rank: Super Contributor
timestamp: April 03, 2025, 08:27:04 pm
content: Wasn't motorboating a "feature" of old super-regenerative radios?

author: TimFox
author_rank: Super Contributor
timestamp: April 03, 2025, 08:28:50 pm
content: No, that was squegging: preventing the regenerative stage from developing an oscillation.Motorboating was found, for example, in 5-tube radios if the power decoupling on the Vbb line had inappropriate time constants, and the variation in supply voltage caused a low-frequency oscillation.

author: Analog Kid
author_rank: Super Contributor
timestamp: April 03, 2025, 09:51:35 pm
content: Well, it may well have been squegging, technically speaking, but didn't people call it "motorboating" back then?I thought that was one of the well-known pitfalls of Armstrong's super-regenerative circuit design.

author: TimFox
author_rank: Super Contributor
timestamp: April 03, 2025, 10:11:35 pm
content: No. Armstrong exploited squegging for his (hard to understand) super-regenerative receiver invention.Motorboating is an amplifier problem. Seehttps://canadianvintageradio.com/wp-content/uploads/2015/03/How-To-Fix-a-Receiver-That-Squeals-and-Motorboats.pdfSee also F E TermanRadio Engineers' Handbook, McGraw Hill 1943, pp 406-410 for motorboating and p 662 for superregenerative receivers.The CRO trace I posted above was for a Clapp LC oscillator using a 7587 Nuvistor tetrode. I fixed the problem by shortening the time constant of the grid-coupling capacitance and the grid leak resistor.Note that the unwanted relaxation oscillation has a frequency of about 1250 Hz, which is typical for squegging. I have encountered motorboating in old radios, with a clear "putt-putt" audible signature at a subsonic repetition rate.

author: RoGeorge
author_rank: Super Contributor
timestamp: April 04, 2025, 05:18:57 am
content: Funny thing,motorboatingis not in the IEEE 100 dictionary, nor in the online Merriam-Webster dictionary.However,motorboatingis listed in the Collins dictionary:QuoteQuoted text fromhttps://www.collinsdictionary.com/us/dictionary/english/motorboating

author: David Hess
author_rank: Super Contributor
timestamp: April 04, 2025, 10:13:39 am
content: Not to be confused with a snivet, which is a negative resistance parasitic oscillation.

author: TimFox
author_rank: Super Contributor
timestamp: April 04, 2025, 02:21:14 pm
content: You will also find "motorboating" in dictionaries that define obscene or improper language.