Attenuators for Pulse Generator

[Sahara]

attenuator-pulse generator

hi to all,

I am having one Pulse Generator, which is having capability to generate 20mVp-p amplitude. One of my application required generation of very low voltage level ie below 10mVp-p. I was planning to purchase new one which is having the below generation capability. but one of my friend told me to purchase atttenuator which seems solve my problem. Impedance of pulse generator is 50 Ohm.

can any one please help me to get the solution out of it?.. is there such attenuators are available? which are they?? ie make, model

also, explore if any other options are available.

 

[FvM]

why its requried 20db attenuator

I guess, that a single 20 dB coaxial BNC attenuator would do. https://www.farnell.com/datasheets/42143.pdf

 

[oldeboots]

generator attenuators

Actually, to cut your signal down by half, a 3 dB attenuator is the right size. They are common for oscilloscopes, with bnc connectors on both ends. Try an instrumentation supply or EBAY.

 

[Sahara]

coaxial pulse generator

hi, oldeboots

i m not looking for attenuators for oscilloscope.

i need pulse generator attenuator, which can generate my 10mVpp signal instead 20mVpp??

 

[FvM]

attenuators generator

Forget about "common for oscilloscopes" and think about the said coaxial attenuators. You should know however, if you intend below 10 mV (> 6 dB attenuation) or exactly 10 mV output (=6 dB attenuation). Usual fixed coaxial attenuators are 3,6,10, and 20 dB. You can also get variable step attenuators, but they are much more expensive and most likely not required, because the pulse generator should have a variable output amplitude as well. The suggested 20 dB attenuator would allow output voltages down to 2 mV.

P.S.: If you have difficulties to understand the meaning of "dB" attenuation, ask wikipedia or similar.

 

[biff44]

attenuator for generator

coaxial attenuators are designed for just such a purpose--attenuating signals. They are precision devices with very large bandwidths designed to both attenuate the signal, AND maintain the published characteristic impedance. What does this all mean? If you have a 50 ohm pulse generator, and a 50 ohm load, and want to drob\p the voltage in half, you would put in a 6 dB attenuator designed for a 50 ohm system. You can figure out the attenuator value by useing ATTEN = 20 LOG (Vout/Vin) = 20 LOG (0.5) = 6 dB. The beauty of all this is that if you also have a length of 50 ohm characteristic impedance line, you can insert it any where in the system and there will be ~ no change.

Of course, if you do not care about impedance matching, if your load is not exactly 50 ohm, etc, you do not need to use an actual attenuator. You could just use a series resistor and reduce the voltage that way. In your case, a simple 100 ohm variable potentiometer in series with the load should work. But, in this case, if you have a long length of coax cable between the load and generator, there will be pulse reflections.

If you want to get fancy, you can make your own "T" or "PI" attenuator with three resistors.

 

[Sahara]

hi,

can you please provide me some more details in three resistor attenuator. or any circuit diagram connection???.. this is something interesting and new to me

 

[biff44]

**broken link removed**