Is noise performance in RF envelope detector important?

[onandon]

I am designing RF envelope detector with CMOS operating in sub-threshold, based on Meyer's topology[JSSC9501,Low-Power Monolithic RF Peak Detector Analysis].

The envelope detector is said to be noisy. Then the noise performance should be an important criteria for the design. However, when I read the papers, no one mention about the noise performance? What could be the reason?

thanks

onandon

 

[khouly]

it will depend on the application of the envelope detector , if i will be used in the receiver , where the signal is weak , so the noise performance is a critical , but some times envelope detectors used in the feedback loops for power amplifiers , so the detected signal is strong , so in this case the noise is not important

khouly

 

[onandon]

it will depend on the application of the envelope detector , if i will be used in the receiver , where the signal is weak , so the noise performance is a critical , but some times envelope detectors used in the feedback loops for power amplifiers , so the detected signal is strong , so in this case the noise is not important

khouly

thank you, khouly.
yeah, lots of paper talk about RF envelope detector in power amplifiers design. In this case, they care the linearity, not the noise.
But, there is still some paper mentioned envelope detector as weak signal detection just after LNA. They do not mention about the noise performance as well. Some tend to increase the gain of LNA to overcome the noisy problem in envelope detector, in turn, the power consumption is increased. It seems not a good option. Two more questions,
1. Is it hard to reduce noise in envelope detector? seems flicker noise is the key.
2. Normally, how much NF or output noise level is considered acceptable in this kind of envelope detector?

thanks
onandon

 

[khouly]

the NF of the detector will be based on ur system spec's like bandwidth , gain of the LNA , NF of the LNA and sure the SNR u want or the BER , so u need to make system calculation to know ur NF

in CMOS the filker noise will dominate the noise performance , if u have the option to use some discrete devices , go 4 the schottky diode they are superior detectors

khouly

 

[onandon]

the NF of the detector will be based on ur system spec's like bandwidth , gain of the LNA , NF of the LNA and sure the SNR u want or the BER , so u need to make system calculation to know ur NF

in CMOS the filker noise will dominate the noise performance , if u have the option to use some discrete devices , go 4 the schottky diode they are superior detectors

khouly

thanks.
unfortunately, i have to design with cmos.
for NF requirement, we need to get it from the calculation based on the system spec. but i am not sure what value is reasonable or achievable. maybe i need to check some commercial products. hopefully they would mention it.

 

[khouly]

check the RFID receivers , based on CMOS

khouly

 

[jecyhale]

When the amplitude of RF is strong, the noise performance become not improtant. Because the SNR will very high.