Design a three channel summing amplifier such that: channel $1 Z_{i n} \geq 10 \mathrm{k} \Omega$ $A_{v}=6 \mathrm{~dB} ;$ channel $2 Z_{\text {in }} \geq 22 \mathrm{k} \Omega, A_{\mathrm{v}}=10 \mathrm{~dB} ;$ and channel $3 Z_{\text {in }} \geq 5 \mathrm{k} \Omega$,
$A_{v}=16 \mathrm{~dB}$