I whant to double a frq. between 200 and 265 MHz. I had tryed to used the
Mini-circuits RK2 doubler and som BP filters, but because of the band pass
200-265MHz it is diffeculd for me to suppress the input frq. and the 3*inp.
to min 50-60dB.
Is there any other ideas to realise this.

--
Frank Mikkelsen

University of Aarhus
Institute of Physics & Astronomi
Nymunkegade, Bygn. 520, room 432
DK-8000 AArhus C
Denmark

Phone +45 89423799 or +45 89423795
Fax: +45 89423794

Frank Mikkelsen wrote:

I whant to double a frq. between 200 and 265 MHz. I had tryed to used the
Mini-circuits RK2 doubler and som BP filters, but because of the band pass
200-265MHz it is diffeculd for me to suppress the input frq. and the 3*inp.
to min 50-60dB.
Is there any other ideas to realise this.

--
Frank Mikkelsen

University of Aarhus
Institute of Physics & Astronomi
Nymunkegade, Bygn. 520, room 432
DK-8000 AArhus C
Denmark

Phone +45 89423799 or +45 89423795
Fax: +45 89423794

Another approach is to lock an oscillator running at the output
frequency to the input. Try dividing the oscillator by two and use that signal
to compare to the input.

Bill K7NOM

Frank Mikkelsen wrote:
I whant to double a frq. between 200 and 265 MHz. I had tryed to used the
Mini-circuits RK2 doubler and som BP filters, but because of the band pass
200-265MHz it is diffeculd for me to suppress the input frq. and the 3*inp.
to min 50-60dB.
Is there any other ideas to realise this.

Full-wave unfiltered rectification, followed by bandpass filter?

--
All relevant people are pertinent.
All rude people are impertinent.
Therefore, no rude people are relevant.
-- Solomon W. Golomb

Frank Mikkelsen wrote:
I whant to double a frq. between 200 and 265 MHz. I had tryed to used
the
Mini-circuits RK2 doubler and som BP filters, but because of the band
pass
200-265MHz it is diffeculd for me to suppress the input frq. and the
3*inp.
to min 50-60dB.
Is there any other ideas to realise this.

You might use a pair of MMIC's in push-push. Get gain AND cancellation of
fundamental and odd harmonics.

W4ZCB

Frank Mikkelsen wrote:
I whant to double a frq. between 200 and 265 MHz. I had tryed to used
the
Mini-circuits RK2 doubler and som BP filters, but because of the band
pass
200-265MHz it is diffeculd for me to suppress the input frq. and the
3*inp.
to min 50-60dB.
Is there any other ideas to realise this.

You might use a pair of MMIC's in push-push. Get gain AND cancellation of
fundamental and odd harmonics.

W4ZCB

Full-wave unfiltered rectification, followed by bandpass filter?

Clifto-

Doesn't full wave produce a symmetrical waveform that minimizes even harmonics?

73, Fred, K4DII

Fred McKenzie wrote:
Full-wave unfiltered rectification, followed by bandpass filter?

Clifto-

Doesn't full wave produce a symmetrical waveform that minimizes even harmonics?

It's not exactly symmetrical. Rectifying a sine wave produces what looks
like a sine wave with pointy lower peaks, at twice the input frequency.
A little decent filtering at 2F, and the pointy lower peaks go away.

--
All relevant people are pertinent.
All rude people are impertinent.
Therefore, no rude people are relevant.
-- Solomon W. Golomb

"Clifton T. Sharp Jr." wrote in message ...
Fred McKenzie wrote:
Full-wave unfiltered rectification, followed by bandpass filter?

Clifto-

Doesn't full wave produce a symmetrical waveform that minimizes even harmonics?

It's not exactly symmetrical. Rectifying a sine wave produces what looks
like a sine wave with pointy lower peaks, at twice the input frequency.
A little decent filtering at 2F, and the pointy lower peaks go away.

Well, actually the whole output wave is at 2* the input, which is I
believe what the OP wanted: a freq doubler. Note that rectifying a
sinewave is the same as multiplying by a square wave of the same
frequency which is +1 when the sine is positive and -1 when it's
negative. You can use trig identities and the fact that the square
wave is its fundamental and all odd harmonics to convince yourself
that the "ideal" full wave rectifier puts out DC, 2*fin, 4*fin, 6*fin,
.... -- just the even harmonics and no odds. It's only because the
rectification is imperfect that the fundamental or odd harmonics get
through. The pointy lower peaks must represent higher order even
harmonics of the input frequency.

Cheers,
Tom

Tom Bruhns wrote:
"Clifton T. Sharp Jr." wrote in message ...
Fred McKenzie wrote:
Full-wave unfiltered rectification, followed by bandpass filter?

Clifto-

Doesn't full wave produce a symmetrical waveform that minimizes even harmonics?

It's not exactly symmetrical. Rectifying a sine wave produces what looks
like a sine wave with pointy lower peaks, at twice the input frequency.
A little decent filtering at 2F, and the pointy lower peaks go away.

Well, actually the whole output wave is at 2* the input, which is I
believe what the OP wanted: a freq doubler. Note that rectifying a
sinewave is the same as multiplying by a square wave of the same
frequency which is +1 when the sine is positive and -1 when it's
negative. You can use trig identities and the fact that the square
wave is its fundamental and all odd harmonics to convince yourself
that the "ideal" full wave rectifier puts out DC, 2*fin, 4*fin, 6*fin,
... -- just the even harmonics and no odds. It's only because the
rectification is imperfect that the fundamental or odd harmonics get
through. The pointy lower peaks must represent higher order even
harmonics of the input frequency.

http://www.rfcafe.com/references/electrical/periodic_series.htm has
a nice exposition of Fourier series for various waveforms, including
half- and full-wave rectified sine waves. The Rubber Bible math table
book used to have the waveforms and Fourier series for them, too.

I first got interested in them when I was about 11, in 1957. Somewhat
later I took the math class where we derived them. It was sort of
interesting to see my childhood friends constructed on a blackboard.

--
Mike Andrews

Tired old sysadmin since 1964

Tom Bruhns wrote:
"Clifton T. Sharp Jr." wrote in message ...
Fred McKenzie wrote:
Full-wave unfiltered rectification, followed by bandpass filter?

Clifto-

Doesn't full wave produce a symmetrical waveform that minimizes even harmonics?

It's not exactly symmetrical. Rectifying a sine wave produces what looks
like a sine wave with pointy lower peaks, at twice the input frequency.
A little decent filtering at 2F, and the pointy lower peaks go away.

Well, actually the whole output wave is at 2* the input, which is I
believe what the OP wanted: a freq doubler. Note that rectifying a
sinewave is the same as multiplying by a square wave of the same
frequency which is +1 when the sine is positive and -1 when it's
negative. You can use trig identities and the fact that the square
wave is its fundamental and all odd harmonics to convince yourself
that the "ideal" full wave rectifier puts out DC, 2*fin, 4*fin, 6*fin,
... -- just the even harmonics and no odds. It's only because the
rectification is imperfect that the fundamental or odd harmonics get
through. The pointy lower peaks must represent higher order even
harmonics of the input frequency.

http://www.rfcafe.com/references/electrical/periodic_series.htm has
a nice exposition of Fourier series for various waveforms, including
half- and full-wave rectified sine waves. The Rubber Bible math table
book used to have the waveforms and Fourier series for them, too.

I first got interested in them when I was about 11, in 1957. Somewhat
later I took the math class where we derived them. It was sort of
interesting to see my childhood friends constructed on a blackboard.

--
Mike Andrews

Tired old sysadmin since 1964