On Tue, 2013-11-26 at 17:20 -0800, Phil Sittner wrote:
>
>
>
> William-
>
> Thanks for your prompt response and the equations. But I need some
> translation since my trig skills are lacking.
>
> -If you input the same frequency with each input 180 degrees apart the
> output should be zero, no DC component no AC component? Or is there an
> output proportional to the difference in amplitudes?
>
> -If you input the same frequency with a phase difference that differs
> from 180 degrees what should one expect as an output?
>
> Phil
> kd6rm
The equations are just the equality for sin-squared, which the NE602
produces if its two inputs are not overdriven. The actual output voltage
depends upon the circuit, and is proportion to the two input amplitudes.
IF you could run it at 1 volt, the output from two 1 volt sinusoids
(same frequency, zero phase between them) is 1/2 volt DC plus 1/2 volt
of sinusoid at double the frequency (the NE602 makes a pretty clean
frequency doubler, as well as using the 1/2 volt DC as a phase detector.
The DC component drops as the phase between the two sinusoids departs
from zero. At ninety degrees the DC drops to zero. Then it starts rising
again, BUT NEGATIVE, peaking at 1/2 volt at 180 degrees. It decreases
again to zero volts at 270 degrees (which is the same as -90 degrees),
then rises back to +1/2 volt as we come full circuit back to 360 degrees
= 0 degrees.
Now actually the NE602 inputs are limited to less than one volt, at
about 1/2 volt peak it starts becoming nonlinear I think (it's been a
long time since I used one, someone can give the exact amplitude limits
for linear operati
| 9433
| 2013-11-26 18:20:08
| William Carver
| Re: NE602--Antenna analyzer
|
On Tue, 2013-11-26 at 17:20 -0800, Phil Sittner wrote: >
>
>
> William-
>
> Thanks for your prompt response and the equations. But I need some
> translation since my trig skills are lacking.
>
> -If you input the same frequency with each input 180 degrees apart the
> output should be zero, no DC component no AC component? Or is there an
> output proportional to the difference in amplitudes?
Sorry, should have emphasized that the NE602 is an analog MULTIPLIER. As long as you don't overload the inputs the output is proportional to the PRODUCT of the two input signalss. The output amplitude will be proporti
| 9434
| 2013-11-26 18:59:44
| Phil Sittner
| Re: NE602--Antenna analyzer
|
Bill- Thank you very much. This circuit is very intriguing so I'm digging deeply into it. Phil ----- Original Message -----
| 9435
| 2013-11-26 19:05:01
| AD7ZU
| Re: NE602--Antenna analyzer
|
The NE602 and derivatives use a gilbert cell as the mixer portion of the chip. There are a host of applications today that still rely on analog multiplication …mixing rf signals to another frequency is but one such application. It is interesting that before the digital days the gilbert cell was designed as an analog multiplier. Some of us ancient folk may still remember wiring up analog computing problems on those peg boards in college.. the multiplier was one of the little plug in blocks…and inside was a gilbert cell.
| 9436
| 2013-11-26 19:22:39
| William Carver
| Re: NE602--Antenna analyzer
|
Yes Phil, its a very nicely done instrument, suited very well to antenna work. After Thanksgiving I'll consider how I might build one myself. W7AAZ On Tue, 2013-11-26 at 18:59 -0800, Phil Sittner wrote:
>
>
>
> Bill-
>
> Thank you very much. This circuit is very intriguing so I'm digging
> deeply into it.
>
> Phil
> ----- Original Message -----
>
| 9437
| 2013-11-26 20:09:16
| Phil Sittner
| Re: NE602--Antenna analyzer
|
William- In researching antenna analyzer designs I happened across Arend's (PA1ARE) site. It was only after starting the build on his design that it was discovered that he became a silent key just a year after he posted it. His club has apparently kept the site up as a memorial to the man. There's some additional bio about him; he died at age 50 from a blood disorder, had worked in the fiber optics industry doing design work and was last employed as a hardware engineer at Delft University. He also had a major interest in solar physics. He sounds like a person I would like to have know. My best wishes to you and your family for a happy Thanksgiving, and again thank you for taking the time to help me understand the operation of these circuits. Good luck with your build. Phil kd6rm ----- Original Message -----
| 9438
| 2013-11-27 02:25:34
| Russell Shaw
| Re: NE602--Antenna analyzer
|
| 9439
| 2013-11-27 16:21:33
| Phil Sittner
| Re: NE602--Antenna analyzer
|
Russell- Talk about an authority,what great credentials. Thank you and everyone else who has taken the time to help me understand the dynamics at play here. As mentioned earlier, this design is quite wonderful and I need to finish the fabrication and try it. Phil ----- Original Message -----
| 9440
| 2013-11-27 16:28:08
| Phil Sittner
| Re: NE602--Antenna analyzer
|
William- There's a couple of hard to find parts for this. Both the loop controller chip, MC145170, and the varactor, BB212, were found on ebay; the first came from Silicon Valley and the second from China. Hard to believe that stuff that was designed in Europe needs to be sourced from China. Happy Thanksgiving and again thanks for your interest and support. Phil kd6rm ----- Original Message -----
| 9441
| 2013-11-27 16:30:07
| Dana Myers
| Re: NE602--Antenna analyzer
|
| 9445
| 2013-11-29 06:11:43
| Eamon Egan
| Re: NE602--Antenna analyzer
|
Hi Phil.
When looking at an analog multiplier, it's the cosine of the phase angle between the signals that determines the average (i.e. lowpassed) version of the output signal. Thus:
0 degrees = +1
+/- 90 degrees = 0
180 degrees = -1
This is the phase angle coefficient. Obviously the output is also proportional to the input signal levels and the conversion gain.
I hope this helps (and that I'm not repeating what someone else said - I haven't been following the thread very carefully).
73
Eamon
VE2EGN or AB1NK
|
| 9447
| 2013-11-29 07:38:39
| Phil Sittner
| Re: NE602--Antenna analyzer
|
Eamon- Thank you helping work my way through this. The EMRFD group has a number of helpful members and is a great resource.Please accept my wishes for a happy holiday season. Phil ----- Original Message -----
| 9449
| 2013-11-29 16:34:59
| Ravi Miranda
| Re: NE602--Antenna analyzer
|
Hello
Would MC145170 be a stumbling block? What if we could use another PLL such as the LMXnnnn series? and a Microchip PIC? That of course would mean redevelopment of the code, assuming of course that we could understand the computation required. Is this achievable and what steps would we need to take? for example is the math like this here? http://www.users.on.net/~endsodds/maths.jpg 73 2E0RVI /Ravi | | | | | | | | | | |