127 bit thermometer to 7 bit binary

[helna]

when a 7 bit flash adc is designed, a thermometer code of 127 bit is obtained. how do we convert it to a 7 bit output and obtain the waveform in CADENCE.
please reply ASAP..

 

[etmabreu]

when a 7 bit flash adc is designed, a thermometer code of 127 bit is obtained. how do we convert it to a 7 bit output and obtain the waveform in CADENCE.
please reply ASAP..

No, with a 7 bit adc you get a 7 bit output and a 7 bit thermometer. With 7 bit you have 128 quantification steps, starting from zero and running up to 127.

 

[helna]

Thanks for the reply...
but still I didn't get it.at present I am having 127 comparators and 127 outputs. our guide asked to convert thermometer code to binary, add the signals in CADENCE.
So how come there is only 7 thermometer codes?
sorry if the doubt is a stupid one.
helna.

 

[etmabreu]

It would help a lot if you post your schematics and diagrams.

128 codes (0 to 127) can be reached by a combination of just 7 bits.
If you want to encode something in base 2 (binary) with 7 bits you reach a maximum of 128 codes.
2^7 = 128

 

[crutschow]

To convert the output of the comparators to a 7-bit code you need a series of gates. Here is an example for 2-bits.

 

[helna]

thanks.saw that circuit.but its ok for fewer bits.what about the 127 comparator outputs that i am having?

 

[helna]

what is the importance of 1 out of N encoder? should we place it before converting it to binary?
any views about fat tree encoder?
please reply ASAP

 

[erikl]

G00gle "thermometer to binary decoder"

 

[xplorin]

127 thermometer to 7 bit binary can be converted using a 128:7 dot compressor. Compressor is used mainly in partial product addition in division which counts the number of ones and gives the corresponding binary estimate. Learn about dot compression. It will be a series of full adders and gates.

Vlsi Digital Signal Processing Systems: Design And Implementation by Keshab K. Parhi. This book might be helpful.

 

[helna]

we already did it

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thanks.but that design is already done previous year.

 

[jayesh]

i am facing the same problem of converting 255 bit thermometer to 8 bit binary converter......so pls. helped me with logic implementation and gate level implementation..............pls.............