- #1
kaancelebi
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We need a very-low-noise amplifier for a special application, and we buy such an amplifier with a noise bandwidth of 2.4 MHz and an amplification of 1000. To test it, we take a set of "perfectly" shielded standard resistors, connect each if these to the amplifier input, and measure the rms output noise voltage in each case. The data are given in the Table below. Calculate the following noise parameters of the amplifier: Equivalent noise input voltage, equivalent noise input current, optimum source resistance Ro, and noise factor F at Ro.
Table of output noise voltages:
R (Ω) ---- Urms (mV)
1 ----- ----- 2.0
10 -------- 2.0
10^2 ----- 2.4
10^3 ----- 4.6
10^4 ----- 15
10^5 ----- 90
10^6 ----- 8.1x10^2
10^7 ------ 8x10^3
i really don't understand what i will do. i know some formula Unoise=(4kBTf)^1/2 ,optimum source resistance , and noise factor but i don't know how i can do circuit , use formula or where can i use these table.
i need help !
Table of output noise voltages:
R (Ω) ---- Urms (mV)
1 ----- ----- 2.0
10 -------- 2.0
10^2 ----- 2.4
10^3 ----- 4.6
10^4 ----- 15
10^5 ----- 90
10^6 ----- 8.1x10^2
10^7 ------ 8x10^3
i really don't understand what i will do. i know some formula Unoise=(4kBTf)^1/2 ,optimum source resistance , and noise factor but i don't know how i can do circuit , use formula or where can i use these table.
i need help !