[sdiy] CMOS CD4046 ring mod??

[media at mail1.nai.net]

At 12:06 AM -0800 12/29/01, Tom May wrote:
>
>I think I was thinking of the 565 PLL, not the 4046.
>
>Phase comparator 2 in a 4046 is not a multiplier, it's a digital
>leading edge sensor thingy, there's a state diagram for it in the
>Motorola CMOS Logic databook (or the Fairchild doc at
>http://www.fairchildsemi.com/ds/CD/CD4046BC.pdf) which makes sense if
>you step through it.

Thanks, I have that document, I tried stepping through it, and it gave me a
headache.

However, this is what it says on p.644 of Horowitz & Hill:

  "Let's begin with a look at the phase detector.  There are actually two
basic types, sometimes referred to as type I and type II.  The type I phase
detector is designed to be driven by analog signals or digital square-wave
signals, whereas the type II phase detector is driven by digital
transitions (edges).  They are typified by the 565 (linear, type I) and the
CMOS 4046, which contains both.
  "The simplest phase detector is the type I (digital), which is simply an
exclusive OR gate.  With low-pass filtering, the graph of the output
voltage versus phase difference is shown, for input square waves of 50%
duty cycle.  The type I (linear) phase detector has similar
output-voltage-versus-phase characteristics, although it's internal
circuitry is actually a 'four-quadrant multiplier,' also known as a
balanced mixer..."

So based on that I reach four conclusions:

1) Horowitz & Hill need a proofreader like OJ needed an alibi.
2) I can see how I was confused.
3) Both of the phase detectors in a CD4046 are digital.
4) The 565 might contain a linear four-quadrant multiplier.


>> I remember seeing a copy of Craig Anderton's Electronic Projects for
>> Musicians in about 1981 which had a ring mod using a 4046, after
>> someone tipped Craig off to the built-in multiplier.
>>
>> Tom.
>>
>> media at mail1.nai.net writes:
>>
>> > I keep reading descriptions of the Type II phase discriminator as a
>> > "balanced mixer" or "four-quadrant multiplier" -- descriptions that are
>> > also used to describe a ring modulator.