What is the simplest analog divider circuit?

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Ahmed Alaa

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Hi all,

What is the simplest circuit to divide two signals without using a gilbert cell?

thnx,
 

Analog voltage/current signals...
 

Yes, an arithmetic divider that operates ideally at any frequency.
 

Ahmed Alaa said:
Yes, an arithmetic divider that operates ideally at any frequency.
Click to expand...

You will have to give more sensible information if you want help. DC-1THz isn't possible. You can make a logamp with a matched transistor pair and an opamp. How many quadrants do you need it to operate over?

Keith
 

an arithmetic divider that operates ideally at any frequency
Click to expand...
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 similar speed, PWM multipliers
have only kHz bandwidth.
 

Actually I am tolerant about the operating frequencies, I just want to know what circuits could divide. You're just stating multipliers but I don't know how to wire them as dividers..are all dividers originally multipliers wired as dividers?
 

all dividers originally multipliers wired as dividers?
Click to expand...
It's at least the case with gm-multipliers. Some can work as divider by connecting an internal amplifier respectively, others need an additional OP. The manufacturer datasheets tell in detail. A log/antilog circuit computes the quotient directly:
Code: 
q = a/b = exp(log(a) - log(b))
 

What about an inverting amplifier with one of the two resistors replaced by a voltage controlled resistor?
 

What about an inverting amplifier with one of the two resistors replaced by a voltage controlled resistor?
Click to expand...
Basically another good suggestion. You have to care however for a linear dependance of either resistance or conductance
on the input voltage, which involves a control loop and two matched variable resistors in practice. It can work with FETs or for
rather low speeds with LDRs.
 

thnx FvM ! I managed to simulate the divider using my multiplier wired as a divider.
 

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