27 Threads found on edaboard.com: Antilog
Regarding compression-decompression: In this context, we're referring to a situation in which we are processing an input signal that has a large dynamic range, and a large Signal/Noise ratio is desired for low level inputs. You can not simply amplify the input, because the output would saturate in the p
Analog Circuit Design :: 06.10.2005 23:38 :: electronics_kumar :: Replies: 10 :: Views: 8994
Hi all, I have some questions related to log and antiloge amplifiers.
1- how does the log and antilog amplifier circuits look like?
2- what does the two circuits do?
3- how does the circuits work?
4- the applications of both log and antilog amplifiers?
5- examples of where we can find these circuits?
I hope to hear from you soon
Analog Circuit Design :: 18.10.2005 02:02 :: Y_me :: Replies: 2 :: Views: 2978
can anyone say me how to realize log and antilog in same fpga hardware using lookup table(LUT),interpolation steps.please send me the codes and other detail to execute my final yr project.
PLD, SPLD, GAL, CPLD, FPGA Design :: 31.12.2009 01:05 :: simalneelifeld :: Replies: 0 :: Views: 792
how abt taking a log of the number and then its antilog? i have studied the implementation (not board level) of thse circuits using Opamp in my course.. any badsic book has them too... hope this helps.. incase u are interested i ll try to get those materials posted here.. good luck.. :)
Analog Circuit Design :: 30.12.2004 13:45 :: cedance :: Replies: 8 :: Views: 749
I'm trying to implement a power function,x to the power of y , in hardware.
y is a real number, not an integer.
Both x and y are variables
i thought of implementing x power y using log function
ie y log(x), but it requires LUT's to store the log and antilog info.
CORDIC algorithms can also be used, but i'm interested in imple
PLD, SPLD, GAL, CPLD, FPGA Design :: 11.04.2005 09:49 :: khaleel :: Replies: 1 :: Views: 1006
hai .... i have some problem .... hope u guys can help ...
if i have a set of numbers ... (10002,10568,14587, .....)
is it posibble to scale the numbers into specific range ... i need to scale the number into (0 to 255).
i only know how to scale the number into (0 to 1)
Take logarithm, process the data, a
Mathematics and Physics :: 09.04.2006 03:15 :: jiveshgovil :: Replies: 2 :: Views: 8496
Yes,it might be better if you use transistors.
Secondly the o/p of both loggers must be connected to negative terminal of summer.
Thirdly,you need antilog, this can be accomplished by using another op-amp which has diode or preferably transistor connected to negative terminal and resistance in feedback
You can also eliminate the summing amplif
Electronic Elementary Questions :: 11.05.2006 05:34 :: sheraz.pervaiz :: Replies: 3 :: Views: 1573
I assume you need "true" multiplication, i.e., not for
modulation/demodulation or similar applications.
One method is using logarithmic amplifiers for both signals, then summing and finally an antilog amplifier. This method uses Op Amps and external transistors.
Analog Circuit Design :: 25.05.2006 14:43 :: zorro :: Replies: 11 :: Views: 9746
i know of no paper but op amps with diodes produce nonlinear outputs. try searching for log and antilog amps in google. Ü
Analog IC Design and Layout :: 13.04.2007 03:52 :: acbalbason :: Replies: 1 :: Views: 503
You must be referring to the standard normal (gaussian) distributions' tail probability (Q function) table.
Log normal is a distrbution where, if you consider the logarithm of the random variable, it is gausian distrbuted. Shadowing (slow fading) in wireless channel is taken as lognormal.
So you could look up tail proability using thg the s
Digital communication :: 04.05.2007 07:32 :: bulx :: Replies: 1 :: Views: 970
Whats the difference between slopes VS curves?
example: zero to +10 volts range
If i say the slope rises from zero to +10 volts it looks like a rise time
But i say the curve rises from zero to +10 volts it looks like what?
Where can i find different terms or names for curves please?
Some curves build or rise differential and other
Electronic Elementary Questions :: 27.04.2008 14:28 :: walters :: Replies: 0 :: Views: 468
Reviewing this classical document, I was aware that Vahab actually didnt't mention if the application is kHz or MHz domain. For low frequency (e. g. audio) range, a log/antilog circuit, either as an IC or built from individual parts, is offering superior dynamic, for high frequency, only gilbert-cell multiplier circuits or thermal detectors are usa
Analog Circuit Design :: 05.12.2008 01:58 :: FvM :: Replies: 4 :: Views: 3368
you have to build log and anti log amplifier. It so difficult.
log-antilog analog mutipliers are of no use in frequency mixing.
Balanced mixers (diode quartetts or analog 4-quadrant multipliers) give the best performance and a considerable suppression of input signals, which is an important advantage, if the output frequency is n
Analog Circuit Design :: 12.05.2009 03:54 :: FvM :: Replies: 4 :: Views: 2376
an arithmetic divider that operates ideally at any frequency
Keep on dreaming.
From the existing analog multiplier/divider variants, only "gilbert cell" (gm multiplier) is wideband. Log/antilog offers higher dynamic range but
is restricted to MHz bandwidth at best, hall sensor multipliers (rather unusual) possibly achieve a sim
Analog Circuit Design :: 06.02.2010 07:19 :: FvM :: Replies: 11 :: Views: 4597
In logarithmic or antilogarithmic Amplifier using OPAMP (IC 741) sometimes we use a diode and sometimes we use a transistor..
Which one is mostly used??
Electronic Elementary Questions :: 11.05.2010 10:44 :: Anirban Mitra :: Replies: 0 :: Views: 3036
A multiplier is basically a nonlinear circuit, needing non-linear elements other than OPs.
Depending on the intended operation (1/2/4-quadrant), dynamic and frequency range, different multiplier circuits or ICs are available. Some of them are
log/antilog mutiplier (1-Q, high dynamic, limited bandwidth)
basic gm-multiplier, also OTA-IC (2-Q, fa
Analog Circuit Design :: 28.12.2010 13:37 :: FvM :: Replies: 4 :: Views: 619
I am looking for Quad matched pair transistor for analog divition.
Need minimum 3 matched pair, two for log and one for antilog.
I found MAT14, Do you have any other part,
Analog Circuit Design :: 29.11.2011 01:09 :: grittinjames :: Replies: 2 :: Views: 518
I'm trying to set up a Linear to Exponential/antilog current source to drive a transistor differential amp (that has a linear response).
Using a Linear current mirror with an input voltage of 0 to 2.5V, converted to approx. 0 to
Analog Circuit Design :: 27.12.2011 14:15 :: juz_ad :: Replies: 3 :: Views: 941
The log/antilog circuit doesn't work as shown and the transfer characteristic isn't calculated correctly. It would work for sqrt(x*y). But to calculate x*y, the adder must have a gain factor of 1 for both inputs. So the output has an unwanted offset of 1*Vbe. For a temperature indepent log/antilog multiplier, you need a third log stage with a const
Digital Signal Processing :: 30.01.2012 13:29 :: FvM :: Replies: 7 :: Views: 872
You need to reconstruct a bipolar signal to get correct fundamental frequency display. The non-linear waveform distortion vy log operation creates harmonics that aren't in the original signal. antilog transformation (if possible according to the magnitude resolution) could improve the spectral display.
Digital Signal Processing :: 02.08.2012 14:16 :: FvM :: Replies: 8 :: Views: 411
There are basically two types of analog dividers:
- based on four quadrant multipliers (e.g. AD734)
- based on log/antilog circuits
The log/antilog designs are slower and restricted to single quadrant operation but offer a higher dynamic range. AD538 is an example of an integrated version, but this circuits can be also build from OPs and trans
Analog Circuit Design :: 05.08.2012 04:29 :: FvM :: Replies: 5 :: Views: 719
The fast way is to...
take the logarithm of your number. (Any base)
Subtract from zero (the log of 1). Or change the sign.
Take the antilog.
This gives you the reciprocal of your original number.
It's easier if your pic has a logarithm table.
Microcontrollers :: 31.08.2012 00:02 :: BradtheRad :: Replies: 1 :: Views: 310
In Pspice, a square root circuit can be easily "designed" by using ABM (analog behaviour modelling).
For a real hardware circuit, you can refer to analog multipliers, see an example in the AD633 datasheet
Or use a suitable combination of log/antilog circuits. The basic conce
Microcontrollers :: 16.09.2012 13:50 :: FvM :: Replies: 1 :: Views: 642
geneiusxie, A/B = antilog (logA -logB), A^B = anti log (B * log A). I think you should brush up on your maths.
jeffrey samuel, sorry, I last worked on analogue computers in 1969 and I can't remember much at all other then the fantastic multi turn pots they used (50mm in diameter!).
Analog Circuit Design :: 01.10.2012 12:39 :: chuckey :: Replies: 10 :: Views: 344
Hi! I have to design a circuit whose output should be the product of the two input voltages. The voltages can vary from -3 to +3 V and max. frequency is 10kHz. I am not supposed to use any analog multiplier IC. I thought of the log-antilog technique but it won't work as I have negative inputs. There was a circuit using MOSFETs in wikibooks but that
Analog Circuit Design :: 07.02.2013 08:05 :: botthe. :: Replies: 1 :: Views: 237
they simply represents reflection back... e.g.
or 10Log(a/b)=-10db (where a is port 1 and b is port 2 of any circuit..( Twoport network) )
means if you insert a signal in port a.... 1/10th part will refelect back andremaing 9/10 part will be transferred forw
RF, Microwave, Antennas and Optics :: 26.02.2013 06:19 :: Ow@i$ :: Replies: 4 :: Views: 345
is there any way we can work the 555 VCO such that its frequency increases when input voltage decreases ?
Didn't you have a similar start a new thread when that thread is only 15 days old ????
Analog Circuit Design :: 28.06.2013 15:42 :: rahdirs :: Replies: 2 :: Views: 355