I have been experimenting with three mixing devices: an RF
double-balanced mixer (MCL SRA-1B), a DFF (74AHCT74), and an EXOR
(74ACT86). The mixer and EXOR give similar results - the sum and
difference frequencies, and a slew of various other products that
need to be filtered out. What was appea
Hi
Flip flops are sampling devices. All samplers can / do act as mixers between
the clock (sampling) frequency and the input (data) frequency. That's all
that's going on. Look at it like a mixer and it all makes sense.
Bob
On Jun 24, 2013, at 8:13 PM, ed breya wrote:
> I am revisiting that t
In message <201306250015.r5p0fgej007...@mail6c40.carrierzone.com>, ed breya wri
tes:
>and trying to get my head around how a DFF can take the
>difference between two frequencies.
Try first to think about what happens if you XOR the two
signals, then convince yourself that the DFF basically does
e. I've had this piece of paper in my notes
for LONG time. =)
Bob - AE6RV
- Original Message -
> From: ed breya
> To: time-nuts@febo.com
> Cc:
> Sent: Monday, June 24, 2013 7:13 PM
> Subject: [time-nuts] Frequency subtraction with D-flip flops
>
> I am rev
I am revisiting that tracking generator reference I brought up here a
while back, and trying to get my head around how a DFF can take the
difference between two frequencies. I have studied and thought about
the various topologies and conditions, and searched online for good
explanations, but ha
In the Austron 2110 is a dual D FF Mixer along with circuitry to get 100 Hz
out. I did a board using 2 XTAL Filter stages and you can get 1 E-12 using
a 100 MHz period counter. Using my previously mentioned Ping Pong counter
at 200 MHz and Offset of 1 Hz at 5 MHz you get 1 Hz out. Resolution
(Original seems to have got lost. Try again)
> More recently we are using two D FF's for mixing in A/V
> applications and very high resolution frequency measurements with
> up to 1 E-15 a second using output frequencies from 0.5 Hz to 100
> Hz.
> Do to attachment limitati
(Original seems to have got lost - try again)
> More recently we are using two D FF's for mixing in A/V
> applications and very high resolution frequency measurements with
> up to 1 E-15 a second using output frequencies from 0.5 Hz to 100
> Hz.
> Do to attachment limitat
Forty years ago I did a digital mixer using three J K FF's to subtract the
IF from the LO for remote monitoring of radio stations. The output is not
symmetrical but great for a frequency counter. Shortly there after Motorola
introduced the MC12000 a D FF intended and widely used for PLL
appl
Thanks, Bruce, for that wonderful phase meter patent reference. Very
interesting.
BTW, if any of you are wondering why the patent mentions comparing 10.23 MHz
(GPS) with a "very accurate" 13.4 MHz, the following paper explains that our
favorite cesium frequency 9192.631770 MHz / 686 = 13.400...
Javier Serrano wrote:
On Tue, Jun 25, 2013 at 4:36 AM, ed breya wrote:
4. It seems to me that whenever fd is much higher than fc (fd>>fc), that
fd could be used instead to trigger the second DFF, which would reduce the
metastability of the first DFF somewhat, and also synchronize the outpu
On Tue, Jun 25, 2013 at 4:36 AM, ed breya wrote:
>
> 4. It seems to me that whenever fd is much higher than fc (fd>>fc), that
> fd could be used instead to trigger the second DFF, which would reduce the
> metastability of the first DFF somewhat, and also synchronize the output
> signal closer to
I still can't tell if my email is messed up. Last time the second
attempt went right through. I'm trying again now. Please excuse if
the redundant original shows up too.
Original message:
I am revisiting that tracking generator reference I brought up here a
while back, and trying to get my he
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