5Mhz signal to dc converter circuit needed

S

SUMNERE

Guest
I'm looking for a non-complex way to convert a 5MHZ signal to a dc level with
little if any ripple. The signal is at 5MHz with amplitude of 0-5 volts. When
the signal is present a + 2.5 to +5 Vdc output is required. When the 5MHz
signal disappears a 0 volt output is required.

Any ideas? Thanks
 
"SUMNERE" <sumnere@aol.com> wrote in message
news:20040226114555.03282.00000395@mb-m23.aol.com...
I'm looking for a non-complex way to convert a 5MHZ signal to a dc level with
little if any ripple. The signal is at 5MHz with amplitude of 0-5 volts. When
the signal is present a + 2.5 to +5 Vdc output is required. When the 5MHz
signal disappears a 0 volt output is required.

Any ideas? Thanks
Click to expand...
Are you basically looking for a frequency to voltage converter??

LM2917 or LM2907 depending on the application, I don't know what its maximum frequency
capability is, but you can check out the specs at National Semiconductor.

Hope that helps.

--
Myron Samila
Toronto, ON Canada
Samila Racing
http://204.101.251.229/myronx19
 
SUMNERE wrote:

I'm looking for a non-complex way to convert a 5MHZ signal to a dc level with
little if any ripple. The signal is at 5MHz with amplitude of 0-5 volts. When
the signal is present a + 2.5 to +5 Vdc output is required. When the 5MHz
signal disappears a 0 volt output is required.

Any ideas? Thanks
Click to expand...

Here is my favorite:

cut what follows into a text file called Detector.asc and open it using
LTSpice: You can then play around with optimising the turn on time
(determined primarily by the ratio of C2/C1), the turn off time
(determined primarily by the C1R2 time constant) and the amount of
ripple while it is on. My solution uses a series dc blocking capacitor
so that you dont have to know which state (high or low) your RF source
is in when no 5Mhz is present.

MikeM

___________________________________________________________________________

Version 4
SHEET 1 880 680
WIRE 192 304 192 240
WIRE 192 176 192 80
WIRE 192 80 144 80
WIRE 80 80 -32 80
WIRE -32 80 -32 176
WIRE -32 240 -32 304
WIRE -32 304 192 304
WIRE -32 368 -32 304
WIRE -512 112 -480 112
WIRE -512 112 -512 192
WIRE -512 352 -512 272
WIRE -160 80 -192 80
WIRE -96 80 -32 80
WIRE -480 112 -352 112
WIRE -192 80 -208 80
WIRE 304 160 304 80
WIRE 304 80 192 80
WIRE 304 240 304 304
WIRE 304 304 192 304
FLAG -32 368 0
FLAG -512 352 0
FLAG -480 112 i
FLAG -192 80 o
FLAG -32 80 c
FLAG 192 80 d
SYMBOL cap 176 176 R0
SYMATTR InstName C1
SYMATTR Value 1000p
SYMBOL SpecialFunctions\\modulate -352 48 R0
WINDOW 3 0 0 Invisible 0
SYMATTR InstName A1
SYMATTR Value mark=5meg space=5meg
SYMBOL voltage -512 176 R0
WINDOW 3 29 154 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 2.5 0.5m 1u 1u 1m 2m)
SYMBOL cap -96 64 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName C2
SYMATTR Value 100p
SYMBOL diode -16 240 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL res 288 144 R0
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL diode 80 96 R270
WINDOW 0 32 32 VTop 0
WINDOW 3 0 32 VBottom 0
SYMATTR InstName D2
SYMATTR Value 1N4148
TEXT -176 384 Left 0 !.tran 3m
TEXT -352 176 Left 0 ;5Mhz 5Vp-p
 
it sounds to me all you need is an RF switch.
a nice little germanium diode as the detector
into a small cap, this signal can drive a
common emitter amp as the inverter that drives
another inverter , the output of this can drive
a current Boost stage(Unity gain)..
that is just off the top of my head , there are more
details that has to be worked out like the resistors etc..
if you don't get any where with this let me know i can
most likely pop up a schematic of something that will work
ok.



SUMNERE wrote:

I'm looking for a non-complex way to convert a 5MHZ signal to a dc level with
little if any ripple. The signal is at 5MHz with amplitude of 0-5 volts. When
the signal is present a + 2.5 to +5 Vdc output is required. When the 5MHz
signal disappears a 0 volt output is required.

Any ideas? Thanks
Click to expand...
 
Does it matter what the rise and fall time for the detector is?

Does it matter what the output impedence is?

If not you can do it with ine diode one capacitor and a resistor.


"SUMNERE" <sumnere@aol.com> wrote in message
news:20040226114555.03282.00000395@mb-m23.aol.com...
I'm looking for a non-complex way to convert a 5MHZ signal to a dc level
with
little if any ripple. The signal is at 5MHz with amplitude of 0-5 volts.
When
the signal is present a + 2.5 to +5 Vdc output is required. When the 5MHz
signal disappears a 0 volt output is required.

Any ideas? Thanks
Click to expand...
 
Scratch that. I read it again and see you want variable output voltage.


"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:_vG%b.14979$HG7.885790@phobos.telenet-ops.be...
Does it matter what the rise and fall time for the detector is?

Does it matter what the output impedence is?

If not you can do it with ine diode one capacitor and a resistor.


"SUMNERE" <sumnere@aol.com> wrote in message
news:20040226114555.03282.00000395@mb-m23.aol.com...
I'm looking for a non-complex way to convert a 5MHZ signal to a dc level
with
little if any ripple. The signal is at 5MHz with amplitude of 0-5
volts.
When
the signal is present a + 2.5 to +5 Vdc output is required. When the
5MHz
signal disappears a 0 volt output is required.

Any ideas? Thanks
Click to expand...
 
"CWatters" (colin.watters@pandoraBOX.be) writes:
Scratch that. I read it again and see you want variable output voltage.

Like I said over in sci.electronics.design, the guy isn't clear
Click to expand...
what he wants. Take a bunch of people, and they will interpret
his vague post multiple ways.

Michael

"CWatters" <colin.watters@pandoraBOX.be> wrote in message
news:_vG%b.14979$HG7.885790@phobos.telenet-ops.be...

Does it matter what the rise and fall time for the detector is?

Does it matter what the output impedence is?

If not you can do it with ine diode one capacitor and a resistor.


"SUMNERE" <sumnere@aol.com> wrote in message
news:20040226114555.03282.00000395@mb-m23.aol.com...
I'm looking for a non-complex way to convert a 5MHZ signal to a dc level
with
little if any ripple. The signal is at 5MHz with amplitude of 0-5
volts.
When
the signal is present a + 2.5 to +5 Vdc output is required. When the
5MHz
signal disappears a 0 volt output is required.

Any ideas? Thanks
Click to expand...
 
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