How to degrade the sensitivity of an Receiver?

[Mac7978]

Dear all,

I am already build an 868MHz ASK receiver using an IC, but i want to degrage its receive sensitivity for some tests. How can i do it?

From the data sheet, this IC has the sensitivity about -100dBm.

Best rgd,

 

[brmadhukar]

Hi,
Use a calibrated attenuator. It is available from Agilent tecnologies. It is accurate to 0.1dB. Be sure to use low loss cable if you are doing any measurements.
B R
Madhukar

 

[vfone]

Better than Agilent and much cheaper are the one from Weinschel
**broken link removed**

 

[flatulent]

A less costly method would be to disconnect it from the regular antenna and solder a short wire to the input.

 

[shogun]

why not design your own attenuator using either a pi or a tee of resistors, you can save some money and you might get better results than just a shorted piece of wire.

Shogun

 

[xxargs]

why not design your own attenuator using either a pi or a tee of resistors, you can save some money and you might get better results than just a shorted piece of wire.

Shogun

Or use piece of high loss koaxial cable depend of how much you need attenuate.

RG174 for example have high loss per meter and not so expensive.
(28.2 dB/30.4 meter (100 ft) @ 900 MHz.)

for this solution needs att reciver impedance and cable impedances
is more or less same - and this atteunate is frecuency depend in
bigger scale.

This solution is very often to building IM-free load for high power
multicarrier measurement.