Need to reduce the Phase by 45 degrees.

[Wicked]

Hello ....

I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees. How
would I do this? RC circuit? I want to keep the amplitute at about 5
volts peak to peak


The freq is 10 Khz. Sine wave 5 volts peak to peak.

If I use a RC circuit? what values?

 

[Robert Baer]

Wicked wrote:

Hello ....

I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees. How
would I do this? RC circuit? I want to keep the amplitute at about 5
volts peak to peak

The freq is 10 Khz. Sine wave 5 volts peak to peak.

If I use a RC circuit? what values?

If the frequency is constant, then the RC depends on the frequency.

 

[Ken Smith]

In article <2031be64.0404052215.143c3d2d@posting.google.com>,
Wicked <Wickedke@aol.com> wrote:

Hello ....

I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees. How
would I do this? RC circuit? I want to keep the amplitute at about 5
volts peak to peak


The freq is 10 Khz. Sine wave 5 volts peak to peak.

If I use a RC circuit? what values?

This really really sounds like homework.


--
--
kensmith@rahul.net forging knowledge

 

[Dbowey]

Wick posted:
<< I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees. How would I
do this? RC circuit? I want to keep the amplitute at about 5 volts peak to
peak


The freq is 10 Khz. Sine wave 5 volts peak to peak.

If I use a RC circuit? what values?

---

Are you looking for an external method, or one that can be done by a mod (if
needed)in the oscillator?

In any case, what is the frequency and phase tolerance requirement?

What type oscillator are you using?

Is tweaking the "frequency" enough to roll-out the 45 degrees not acceptable?
Freq would still be 10 kHz.

And just for my idle curiosity, what is to be the recipient of the signal?

Don

 

[Wicked]

This really really sounds like homework.


--

No, its actually part of a bigger project. I just can get the
simulation working on p-spice.

 

[Wicked]

dbowey@aol.com (Dbowey) wrote in message news:<20040406144727.09718.00000646@mb-m24.aol.com>...

Wick posted:
I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees. How would I
do this? RC circuit? I want to keep the amplitute at about 5 volts peak to
peak


The freq is 10 Khz. Sine wave 5 volts peak to peak.

If I use a RC circuit? what values?

---

Are you looking for an external method, or one that can be done by a mod (if
needed)in the oscillator?

In any case, what is the frequency and phase tolerance requirement?

What type oscillator are you using?

Is tweaking the "frequency" enough to roll-out the 45 degrees not acceptable?
Freq would still be 10 kHz.

And just for my idle curiosity, what is to be the recipient of the signal?

Don

Hello,

I am looking for an external method. The signal is coming out of an
AD633 , which i need to match the phase up with my referance frequency
I want to get both of these freq. in phase with each other...the
closest possible. I was thinking about a simple RC circuit....

"Is tweaking the "frequency" enough to roll-out the 45 degrees not
acceptable? Freq would still be 10 kHz." .... sorry I dont understand
this.

The recipient is going to be an anolog mux with is going to select
between two signals dependig on logic 1 and logic 0

 

[Wicked]

Robert Baer <robertbaer@earthlink.net> wrote in message news:<40725D0A.D567BEB8@earthlink.net>...

Wicked wrote:

Hello ....

I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees. How
would I do this? RC circuit? I want to keep the amplitute at about 5
volts peak to peak

The freq is 10 Khz. Sine wave 5 volts peak to peak.

If I use a RC circuit? what values?

If the frequency is constant, then the RC depends on the frequency.

- Yes, the freq is going to be constant.

 

[John Popelish]

Wicked wrote:

Hello,

I am looking for an external method. The signal is coming out of an
AD633 , which i need to match the phase up with my referance frequency
I want to get both of these freq. in phase with each other...the
closest possible. I was thinking about a simple RC circuit....

"Is tweaking the "frequency" enough to roll-out the 45 degrees not
acceptable? Freq would still be 10 kHz." .... sorry I dont understand
this.

The recipient is going to be an anolog mux with is going to select
between two signals dependig on logic 1 and logic 0

An RC high pass divider (signal into capacitor, output between cap and
resistor, resistor grounded) will produce 45 degrees of phase lead at
the frequency where the capacitive reactance equals the resistance.
Mathematically, R=1/(2*pi*f*c).

However, the output amplitude will be 70.7% of the input amplitude.

If you make a pole zero phase lead all pass filter with an opamp, not
only will the amplitude be independent of frequency, you can tune the
phase shift without altering the gain.

This sort of thing is made by adding an opamp and two equal resistors
to the phase lead divider I mentioned above. You connect the output
pf that divider to the + input of the opamp, and connect the divider
made up of the two equal resistors from input signal to the output of
the opamp, with the middle tap connected to the - input of the opamp.
The resistor after the cap can be an adjustable resistor to trim the
phase shift.

--
John Popelish

 

[Spajky]

On 6 Apr 2004 20:05:19 -0700, Wickedke@aol.com (Wicked) wrote:

Robert Baer <robertbaer@earthlink.net> wrote in message news:<40725D0A.D567BEB8@earthlink.net>...
Wicked wrote:

I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees.

The freq is 10 Khz. Sine wave 5 volts peak to peak.

- Yes, the freq is going to be constant.

What about using 2 serially connected TV analog delay lines of 64ms ?
(not sure if they are ms or microSec ..) of color decoder ...

-- Regards, SPAJKY ÂŽ
& visit my site @ http://www.spajky.vze.com
"Tualatin OC-ed / BX-Slot1 / inaudible setup!"
E-mail AntiSpam: remove ##

 

[Ted Wilson]

John Popelish <jpopelish@rica.net> wrote in message news:<40737AE3.A20F7465@rica.net>...

[snip]

An RC high pass divider (signal into capacitor, output between cap and
resistor, resistor grounded) will produce 45 degrees of phase lead at
the frequency where the capacitive reactance equals the resistance.
Mathematically, R=1/(2*pi*f*c).

However, the output amplitude will be 70.7% of the input amplitude.

If you make a pole zero phase lead all pass filter with an opamp, not
only will the amplitude be independent of frequency, you can tune the
phase shift without altering the gain.

This sort of thing is made by adding an opamp and two equal resistors
to the phase lead divider I mentioned above. You connect the output
pf that divider to the + input of the opamp, and connect the divider
made up of the two equal resistors from input signal to the output of
the opamp, with the middle tap connected to the - input of the opamp.
The resistor after the cap can be an adjustable resistor to trim the
phase shift.

Are you 'Trolling' here John?

I did a posting here last year on the subject of an all-pass
phase-lead circuit called 'The all-pass conundrum'.

Basically, it seems it can't be done. No matter what configuration of
R/C or L/C you use, you get an output voltage vector that rotates
clockwise with increasing frequency, so the output phase progressively
lags as frequency increases.

The only way, (in theory), to get what you want is if either the R or
the C is negative, but the combination of negative resistance and
capacitance, or resistance and negative capacitance, always results in
either oscillation or latch-up.

However, the all-pass phase-lag circuit gives us a means of generating
phase lag, without the normally attendant attenuation so, by analogy,
I've felt for a long time now that we aught to be able to do the
converse - i.e. phase lead without gain.

The trite answer you invariably get when discussing an all-pass
phase-lead is that it would amount to a time-machine. Whilst I can
see what they mean, I've never entirely bought that myself. The fact
is, we can and do generate phase-lead, without the need for the use of
a Tardis, albeit accompanied by increasing gain with increasing
frequency, with all the problems that invariably brings. So, if we
can generate phase-lag, without attenuation, why can't we generate
phase-lead without gain?

All I can say is that I've come at the problem from all sorts of
different angles and I've never been able to find a solution.

Regards

Ted Wilson

 

[Jan Panteltje]

On a sunny day (Wed, 07 Apr 2004 11:44:20 +0200) it happened Spajky
<Spajky##@volja.net> wrote in <j7i770dci14snsfo3gf0ig8hbb0t04d2af@4ax.com>:

On 6 Apr 2004 20:05:19 -0700, Wickedke@aol.com (Wicked) wrote:

Robert Baer <robertbaer@earthlink.net> wrote in message news:<40725D0A.D567BEB8@earthlink.net>...
Wicked wrote:

I need some help please!

I have a sine wave which I need to reduce the phase by 45 degrees.

The freq is 10 Khz. Sine wave 5 volts peak to peak.

- Yes, the freq is going to be constant.

What about using 2 serially connected TV analog delay lines of 64ms ?
(not sure if they are ms or microSec ..) of color decoder ...

64 us, 2 x = 128 us, one 10kHz period = 100 us, where is the 45 degrees?

Delay line is original idea though
JP

 

[John Popelish]

Ted Wilson wrote:

John Popelish <jpopelish@rica.net> wrote in message news:<40737AE3.A20F7465@rica.net>...

[snip]


An RC high pass divider (signal into capacitor, output between cap and
resistor, resistor grounded) will produce 45 degrees of phase lead at
the frequency where the capacitive reactance equals the resistance.
Mathematically, R=1/(2*pi*f*c).

However, the output amplitude will be 70.7% of the input amplitude.

If you make a pole zero phase lead all pass filter with an opamp, not
only will the amplitude be independent of frequency, you can tune the
phase shift without altering the gain.

This sort of thing is made by adding an opamp and two equal resistors
to the phase lead divider I mentioned above. You connect the output
pf that divider to the + input of the opamp, and connect the divider
made up of the two equal resistors from input signal to the output of
the opamp, with the middle tap connected to the - input of the opamp.
The resistor after the cap can be an adjustable resistor to trim the
phase shift.

Are you 'Trolling' here John?

I did a posting here last year on the subject of an all-pass
phase-lead circuit called 'The all-pass conundrum'.

Basically, it seems it can't be done. No matter what configuration of
R/C or L/C you use, you get an output voltage vector that rotates
clockwise with increasing frequency, so the output phase progressively
lags as frequency increases.

The only way, (in theory), to get what you want is if either the R or
the C is negative, but the combination of negative resistance and
capacitance, or resistance and negative capacitance, always results in
either oscillation or latch-up.

However, the all-pass phase-lag circuit gives us a means of generating
phase lag, without the normally attendant attenuation so, by analogy,
I've felt for a long time now that we aught to be able to do the
converse - i.e. phase lead without gain.

The trite answer you invariably get when discussing an all-pass
phase-lead is that it would amount to a time-machine. Whilst I can
see what they mean, I've never entirely bought that myself. The fact
is, we can and do generate phase-lead, without the need for the use of
a Tardis, albeit accompanied by increasing gain with increasing
frequency, with all the problems that invariably brings. So, if we
can generate phase-lag, without attenuation, why can't we generate
phase-lead without gain?

All I can say is that I've come at the problem from all sorts of
different angles and I've never been able to find a solution.

Regards

Ted Wilson

I don't think a phase lead implies predicting the future, because it
only works during repeating cycles. Think of the phase of a cycle as
a point on the edge of a rotating disk. A phase shift circuit just
moves the point on the edge, but the cycles proceed just the same.

--
John Popelish

 

[Jim Thompson]

On Wed, 07 Apr 2004 19:59:50 -0400, John Popelish <jpopelish@rica.net>
wrote:

Ted Wilson wrote:

[snip]
I don't think a phase lead implies predicting the future, because it
only works during repeating cycles. Think of the phase of a cycle as
a point on the edge of a rotating disk. A phase shift circuit just
moves the point on the edge, but the cycles proceed just the same.

The OP was less than lucid. Would shifting 315° do what he wants, or
should he shift his "reference"?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Spajky]

On Wed, 07 Apr 2004 16:21:23 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

64 us, 2 x = 128 us, one 10kHz period = 100 us, where is the 45 degrees?

.... yeah, I was a bit sleepy... but anyway:
delays 1 perod + ~1/4 of it (0,28us) ... if only phase matters & does
not a shift of one period ... was just an idea ( a deegre more or less
....)


--
Regards, SPAJKY ÂŽ
& visit my site @ http://www.spajky.vze.com
"Tualatin OC-ed / BX-Slot1 / inaudible setup!"
E-mail AntiSpam: remove ##

 

[Jan Panteltje]

On a sunny day (Thu, 08 Apr 2004 04:37:58 +0200) it happened Spajky
<Spajky##@volja.net> wrote in <5rd970p9orki6a8q0ooq0u9i9h46mv08jc@4ax.com>:

On Wed, 07 Apr 2004 16:21:23 GMT, Jan Panteltje
pNaonStpealmtje@yahoo.com> wrote:

64 us, 2 x = 128 us, one 10kHz period = 100 us, where is the 45 degrees?

... yeah, I was a bit sleepy... but anyway:
delays 1 perod + ~1/4 of it (0,28us) ... if only phase matters & does
not a shift of one period ... was just an idea ( a deegre more or less
...)

Yes OK, the rest could be done with some RC perhaps, maybe 48 is enough.
I like the delay line idea.
But you'd have to AM or FM modulate that 10 kHz on a 4,43 MHz carrier
(I have done that, for tri-PAL, both AM FM, now there is an interesting
subject, tri-PAL, now we are talking 1970ties was RGB line sequential) and
then demodulate again.
That may easily give an additional us delays or so.
This beacuse those glass delay lines are designed to operate at the color
subcarrier (tuned ciruit interface).
JP

 

[Spajky]

On Thu, 08 Apr 2004 17:58:06 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

Yes OK, the rest could be done with some RC perhaps, maybe 48 is enough.
I like the delay line idea.

well, if someone can grab those pre-history analog delay line chips
used in solid state reverberating systems... could be done also with
them (maybe found on some "garage" sales)
They could do few ms delays/chip; the lower the frequency was,
the longer delay could be made, regulation was with a pot., there was
a limit approx. @ 10kHz to use them as IR ...

But there could be also an analog meccanical solution:
just take two cristal gramophone pick ups (yep, that´s also a
historical material...), drive one with a signal, pick up the signal
from another (delayed!), to connect them between meccanically, use a
piece of plastic stick layed accross their pick-up points (where
previously needle support was!). The delay is proportional to the
plastic stick lenght! Funny, but IMHO would work!

the stick could be only few cm long for a 25us (45°) delay ...
"fine" tuning could be done by moving one pick-up closer or further
from another ...

On this principle way time ago I made an analog reverb with springs
(instead of a plastic stick... ) worked like a charm & needed only 2 x
2 transistor stages for drive/pick up signals leveling around
150mV/47k ... )

EVEN simplier solution:
take two dead modems & use their piezo speakers on the same principle
as before mounting them in small isolated tube very close facing their
membranes; the delay of 25us thu air could be reached in less than 1cm
distance between their membranes; on the pick up side the signal
should be delayed for proper amount of time (phase) regarding the
input signal at that required frequency ...

..... sometimes "high" technology solutions work worse than simple
idiot proof solutions ... ))



--
Regards, SPAJKY ÂŽ
& visit my site @ http://www.spajky.vze.com
"Tualatin OC-ed / BX-Slot1 / inaudible setup!"
E-mail AntiSpam: remove ##

 

[Dbowey]

Wicked posted:

<<
I am looking for an external method. The signal is coming out of an
AD633 , which i need to match the phase up with my referance frequency
I want to get both of these freq. in phase with each other...the
closest possible. I was thinking about a simple RC circuit....

The recipient is going to be an anolog mux with is going to select
between two signals dependig on logic 1 and logic 0
---

Assuming there is an external method to shift the phase of the 10kHz signal,
achieving a phase match with your reference frequency, what process will
maintain the match? Are they phase locked? If not, this is a pointless
excercize.

Don

 

[N. Thornton]

edward.wilson@baesystems.com (Ted Wilson) wrote in message news:<88bec0a6.0404070743.6d3905f3@posting.google.com>...

Are you 'Trolling' here John?

I did a posting here last year on the subject of an all-pass
phase-lead circuit called 'The all-pass conundrum'.

Basically, it seems it can't be done. No matter what configuration of
R/C or L/C you use, you get an output voltage vector that rotates
clockwise with increasing frequency, so the output phase progressively
lags as frequency increases.

However, the all-pass phase-lag circuit gives us a means of generating
phase lag, without the normally attendant attenuation so, by analogy,
I've felt for a long time now that we aught to be able to do the
converse - i.e. phase lead without gain.

The trite answer you invariably get when discussing an all-pass
phase-lead is that it would amount to a time-machine. Whilst I can
see what they mean, I've never entirely bought that myself.

If you imagine a sudden alteration in the waveform travelling through
your phase lead filter, the filter would have to produce a new output
waveform before it had received the necessary new input waveform that
gives it the necessary information on which to form its new output
waveform. Yeah? In other words it is a time machine. Hence it is
unrealisable.

Now you could in principle do it if the filter has access to a
prediction of what input is going to come along, and that is not hard
to obtain in many cases. Sometimes we know what lies ahead for the
input signal. And sometimes we dont know but can arrange to find out.

For some purposes you could use a relative future rather than real
future by delaying the whole signal to the input of the filter, but
letting the filter see the undelayed signal as well. This way the
filter sees the relative future of the delayed signal, and could
indeed produce a phase lead version of it... though with a fixed time
delay. An obvious way to implement this would be in software.

The fact
is, we can and do generate phase-lead, without the need for the use of
a Tardis, albeit accompanied by increasing gain with increasing
frequency, with all the problems that invariably brings.

Well, I'd like to hear what you have in mind there.

So, if we
can generate phase-lag, without attenuation, why can't we generate
phase-lead without gain?

At this time I could only offer a very basic and incomplete answer:
the fact that we can see the past doesnt mean we can see the future.
However I do think we can move beyond that.

The only way, (in theory), to get what you want is if either the R or
the C is negative, but the combination of negative resistance and
capacitance, or resistance and negative capacitance, always results in
either oscillation or latch-up.

Just as an aside, I dont know the circuits you have in mind, but is
the problem due to positive feedback? I have used stable positive
feedback on amplifiers, there are ways to do it... but the real points
on this one are further down the post.

All I can say is that I've come at the problem from all sorts of
different angles and I've never been able to find a solution.

Regards, NT

 

[Jan Panteltje]

On a sunny day (09 Apr 2004 01:11:38 GMT) it happened dbowey@aol.com (Dbowey)
wrote in <20040408211138.01261.00000055@mb-m14.aol.com>:

Wicked posted:


I am looking for an external method. The signal is coming out of an
AD633 , which i need to match the phase up with my referance frequency
I want to get both of these freq. in phase with each other...the
closest possible. I was thinking about a simple RC circuit....

The recipient is going to be an anolog mux with is going to select
between two signals dependig on logic 1 and logic 0

How about some hundreds of meters coax?