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From: George Herold on 14 Jun 2010 21:35
On Jun 14, 3:29 pm, John Larkin
<jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote:
> On Mon, 14 Jun 2010 12:12:17 -0700 (PDT), George Herold
>
> <gher...(a)teachspin.com> wrote:
>
> >Could someone tell me what squegging is?  A google search gives hints
> >of something like motor-boating, but different?
>
> We're referring to an oscillator that oscillates in bursts, rather
> than continuously. A resonator connected to a negative resistance
> doesn't squegg, but on the other hand its amplitude builds to infinite
> (for certain values of infinite) at a rate determined by Q.
>
> You can think of an LC resonator as having a 1st order response,
> measuring oscillation envelope versus drive. Oscillators squegg when
> some amplitude limiting mechanism adds additional time delays or
> memory, more poles in the control loop, like the capacitor in the base
> of my circuit. A bigger cap reduces the tendency to squegg.
>
> A superregen receiver is a squegging-on-purpose RF oscillator. That's
> a fascinating circuit.
>
> John

Hmm, OK something like motorboating gone to the extreme.. enough
amplitude modultaion to shut the oscillator off for some time. (?)
Does the squegg rate stay constant in a sugerregen receiver? I'm not
real sure what a superregen reciever is, anything like a marginal
oscillator?

George H.
From: Phil Hobbs on 14 Jun 2010 23:57
On 6/14/2010 3:29 PM, John Larkin wrote:
> On Mon, 14 Jun 2010 12:12:17 -0700 (PDT), George Herold
> <gherold(a)teachspin.com> wrote:
>
>
>>
>> Could someone tell me what squegging is? A google search gives hints
>> of something like motor-boating, but different?
>>
>
> We're referring to an oscillator that oscillates in bursts, rather
> than continuously. A resonator connected to a negative resistance
> doesn't squegg, but on the other hand its amplitude builds to infinite
> (for certain values of infinite) at a rate determined by Q.
>
> You can think of an LC resonator as having a 1st order response,
> measuring oscillation envelope versus drive. Oscillators squegg when
> some amplitude limiting mechanism adds additional time delays or
> memory, more poles in the control loop, like the capacitor in the base
> of my circuit. A bigger cap reduces the tendency to squegg.
>
> A superregen receiver is a squegging-on-purpose RF oscillator. That's
> a fascinating circuit.
>
> John
>
>

Using squegging to quench a superregen is a way to save tubes, rather
than anything inherent to the superregen principle.

You can find a copy, there's a really beautiful little book by J. R.
Whitehead entitled "Superregenerative Receivers", part of the "Modern
Radio Techniques" series edited by J. R. Ratcliffe. Highly
recommended. (Ratcliffe was an amazing character too, btw.)


Cheers

Phil Hobbs

(Currently wrestling gila monsters in Albuquerque NM. [Just kidding
about the gila monsters.])
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net
From: John Larkin on 15 Jun 2010 00:47
On Mon, 14 Jun 2010 23:57:59 -0400, Phil Hobbs
<pcdhSpamMeSenseless(a)electrooptical.net> wrote:

>On 6/14/2010 3:29 PM, John Larkin wrote:
>> On Mon, 14 Jun 2010 12:12:17 -0700 (PDT), George Herold
>> <gherold(a)teachspin.com> wrote:
>>
>>
>>>
>>> Could someone tell me what squegging is? A google search gives hints
>>> of something like motor-boating, but different?
>>>
>>
>> We're referring to an oscillator that oscillates in bursts, rather
>> than continuously. A resonator connected to a negative resistance
>> doesn't squegg, but on the other hand its amplitude builds to infinite
>> (for certain values of infinite) at a rate determined by Q.
>>
>> You can think of an LC resonator as having a 1st order response,
>> measuring oscillation envelope versus drive. Oscillators squegg when
>> some amplitude limiting mechanism adds additional time delays or
>> memory, more poles in the control loop, like the capacitor in the base
>> of my circuit. A bigger cap reduces the tendency to squegg.
>>
>> A superregen receiver is a squegging-on-purpose RF oscillator. That's
>> a fascinating circuit.
>>
>> John
>>
>>
>
>Using squegging to quench a superregen is a way to save tubes, rather
>than anything inherent to the superregen principle.

Yes, there are externally quenched superregens, but they're not as
common, or as elegant.




>
>You can find a copy, there's a really beautiful little book by J. R.
>Whitehead entitled "Superregenerative Receivers", part of the "Modern
>Radio Techniques" series edited by J. R. Ratcliffe. Highly
>recommended. (Ratcliffe was an amazing character too, btw.)
>

Sounds good. I'll look for it.

>John

>
>Cheers
>
>Phil Hobbs
>
>(Currently wrestling gila monsters in Albuquerque NM. [Just kidding
>about the gila monsters.])

From: John Larkin on 15 Jun 2010 00:54
On Mon, 14 Jun 2010 18:35:39 -0700 (PDT), George Herold
<gherold(a)teachspin.com> wrote:

>On Jun 14, 3:29�pm, John Larkin
><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote:
>> On Mon, 14 Jun 2010 12:12:17 -0700 (PDT), George Herold
>>
>> <gher...(a)teachspin.com> wrote:
>>
>> >Could someone tell me what squegging is? �A google search gives hints
>> >of something like motor-boating, but different?
>>
>> We're referring to an oscillator that oscillates in bursts, rather
>> than continuously. A resonator connected to a negative resistance
>> doesn't squegg, but on the other hand its amplitude builds to infinite
>> (for certain values of infinite) at a rate determined by Q.
>>
>> You can think of an LC resonator as having a 1st order response,
>> measuring oscillation envelope versus drive. Oscillators squegg when
>> some amplitude limiting mechanism adds additional time delays or
>> memory, more poles in the control loop, like the capacitor in the base
>> of my circuit. A bigger cap reduces the tendency to squegg.
>>
>> A superregen receiver is a squegging-on-purpose RF oscillator. That's
>> a fascinating circuit.
>>
>> John
>
>Hmm, OK something like motorboating gone to the extreme.. enough
>amplitude modultaion to shut the oscillator off for some time. (?)
>Does the squegg rate stay constant in a sugerregen receiver? I'm not
>real sure what a superregen reciever is, anything like a marginal
>oscillator?

It's an oscillator that is periodically quenched and allowed to
restart. Ideally, when it's off, it's allowed to crawl back up towards
oscillation through an exponentially decaying bias voltage, so it's
creeping up on oscillation. The slightest bit of ambient RF, as from
an antenna, makes the oscillation start sooner. The result is that the
duty cycle of oscillation, hence the supply current, depends on the
external RF.

A single-transistor or tube superregen can drive headphones from a
microvolt RF signal, can detect CW or AM or FM, and can have pretty
good selectivity. It's an amazing circuit.

John

From: baron on 15 Jun 2010 07:16
George Herold Inscribed thus:

> On Jun 14, 3:29 pm, John Larkin
> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote:
>> On Mon, 14 Jun 2010 12:12:17 -0700 (PDT), George Herold
>>
>> <gher...(a)teachspin.com> wrote:
>>
>> >Could someone tell me what squegging is?  A google search gives
>> >hints of something like motor-boating, but different?
>>
>> We're referring to an oscillator that oscillates in bursts, rather
>> than continuously. A resonator connected to a negative resistance
>> doesn't squegg, but on the other hand its amplitude builds to
>> infinite (for certain values of infinite) at a rate determined by Q.
>>
>> You can think of an LC resonator as having a 1st order response,
>> measuring oscillation envelope versus drive. Oscillators squegg when
>> some amplitude limiting mechanism adds additional time delays or
>> memory, more poles in the control loop, like the capacitor in the
>> base of my circuit. A bigger cap reduces the tendency to squegg.
>>
>> A superregen receiver is a squegging-on-purpose RF oscillator. That's
>> a fascinating circuit.
>>
>> John
>
> Hmm, OK something like motorboating gone to the extreme.. enough
> amplitude modultaion to shut the oscillator off for some time. (?)
> Does the squegg rate stay constant in a sugerregen receiver? I'm not
> real sure what a superregen reciever is, anything like a marginal
> oscillator?
>
> George H.

Its a technique by which an amplifier is held on the verge of
oscillation by positive feedback, at which point the gain is very high.
By causing the oscillation to be quenched at the instant it starts is
where the "Super" bit comes from in "Superregenerative". Commonly used
in radio receivers where a single active device is used to both amplify
the incoming RF, demodulate it and amplify the resultant AF, often
driving headphones directly. Often frowned upon because of the
interference that can be caused by radiated RF.

--
Best Regards:
Baron.
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