Het meest linkse blokje van het blokschema bevat dit:
We zien dat:
[imath] U = - \frac{ \mathrm{R}_2 }{ \mathrm{R}_1 } \cdot U_{in} \,\,\,\,\,\,\,\, (1) [/imath]
Laat:
[imath] \mathrm{R}_6 = ( \alpha \, \mathrm{R}_3 ) // \{ (1 - \alpha)\, \mathrm{R}_ 4 \, + \, ( \alpha \, \mathrm{R}_4 ) // \mathrm{R}_5 \} \,\,\,\,\,\,\,\, (2) [/imath]
[imath] \mathrm{R}_7 = (1 - \alpha)\, \mathrm{R}_ 4 \, + \, ( \alpha \, \mathrm{R}_4 ) // \mathrm{R}_5 \,\,\,\,\,\,\,\, (3) [/imath]
Zodat:
[imath] \mathrm{R}_6 = ( \alpha \, \mathrm{R}_3 ) // \mathrm{R}_7 [/imath]
[imath] \mathrm{R}_6 = \frac{ ( \alpha \, \mathrm{R}_3 ) \cdot \mathrm{R}_7 }{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } [/imath]
[imath] \mathrm{R}_6 = \frac{ \alpha \, \mathrm{R}_7 }{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } \cdot \, \mathrm{R}_3 \,\,\,\,\,\,\,\, (4) [/imath]
[imath] \mathrm{R}_7 = (1 - \alpha)\, \mathrm{R}_ 4 \, + \, ( \alpha \, \mathrm{R}_4 ) // \mathrm{R}_5 [/imath]
[imath] \mathrm{R}_7 = (1 - \alpha)\, \mathrm{R}_ 4 \, + \, \frac{ \alpha \, \mathrm{R}_4 \cdot \mathrm{R}_5}{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 } [/imath]
[imath] ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 ) \cdot \mathrm{R}_7 = (1 - \alpha)\, \mathrm{R}_ 4 \cdot ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 ) \, + \, \alpha \, \mathrm{R}_4 \cdot \mathrm{R}_5 [/imath]
[imath] ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 ) \cdot \mathrm{R}_7 = (1 - \alpha) \cdot ( \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 ) \, + \, \alpha \, \mathrm{R}_4 \cdot \mathrm{R}_5 [/imath]
[imath] ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 ) \cdot \mathrm{R}_7 = ( \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 ) \, - \, ( \alpha^2 \, \mathrm{R}_4^2 \, + \, \alpha \, \mathrm{R}_ 4 \, \mathrm{R}_5 ) \, + \, \alpha \, \mathrm{R}_4 \cdot \mathrm{R}_5 [/imath]
[imath] ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 ) \cdot \mathrm{R}_7 = \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 \,\,\,\,\,\,\,\, (5) [/imath]
Dan zien we dat:
[imath] V = \frac{\mathrm{R}_6}{ (1 - \alpha) \mathrm{R}_3 + \mathrm{R}_6 } \cdot U \,\,\,\,\,\,\,\, (6) [/imath]
De teller T kunnen we herschrijven als:
[imath] T = \mathrm{R}_6 [/imath]
[imath] T = \alpha \, \mathrm{R}_7 \cdot \frac{1}{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } \cdot \, \mathrm{R}_3 \,\,\,\,\,\,\,\, (7) [/imath]
En de noemer N als:
[imath] N = (1 - \alpha) \mathrm{R}_3 + \mathrm{R}_6 [/imath]
[imath] N = (1 - \alpha) \mathrm{R}_3 + \frac{ \alpha \, \mathrm{R}_7 }{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } \cdot \, \mathrm{R}_3 [/imath]
[imath] N = ( (1 - \alpha) \, + \, \frac{ \alpha \, \mathrm{R}_7 }{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } ) \cdot \, \mathrm{R}_3 [/imath]
[imath] N = ( (1 - \alpha) \cdot ( \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 ) \, + \, \alpha \, \mathrm{R}_7 ) \cdot \, \frac{ 1 }{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } \cdot \mathrm{R}_3 [/imath]
[imath] N = ( ( \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 ) \, - \, ( \alpha^2 \, \mathrm{R}_3 \, + \, \alpha \, \mathrm{R}_7 ) \, + \, \alpha \, \mathrm{R}_7 ) \cdot \, \frac{ 1 }{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } \cdot \mathrm{R}_3 [/imath]
[imath] N = ( \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 \, - \, \alpha^2 \, \mathrm{R}_3 ) \cdot \, \frac{ 1 }{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 } \cdot \mathrm{R}_3 \,\,\,\,\,\,\,\, (8) [/imath]
Dus:
[imath] V = \frac{\alpha \, \mathrm{R}_7}{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 \, - \, \alpha^2 \, \mathrm{R}_3 } \cdot U \,\,\,\,\,\,\,\, (9) [/imath]
Vervolgens zien we dat:
[imath] W = \frac{ (\alpha \, \mathrm{R}_4) // \mathrm{R}_5 }{ (1 - \alpha) \, \mathrm{R}_4 \, + \, (\alpha \, \mathrm{R}_4) // \mathrm{R}_5 } \cdot V \,\,\,\,\,\,\,\, (10) [/imath]
Hier schrijven we de teller als T' en de noemer als N'. Dus:
[imath] T' = (\alpha \, \mathrm{R}_4) // \mathrm{R}_5 [/imath]
[imath] T' = \frac{ \alpha \, \mathrm{R}_4 \, \cdot \, \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 } [/imath]
[imath] T' = \frac{ \alpha \, \cdot \, \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 } \cdot \mathrm{R}_4 [/imath]
[imath] T' = \alpha \, \cdot \, \mathrm{R}_5 \cdot \frac{\mathrm{R}_4}{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 } \,\,\,\,\,\,\,\, (11) [/imath]
[imath] N' = (1 - \alpha) \, \mathrm{R}_4 \, + \, (\alpha \, \mathrm{R}_4) // \mathrm{R}_5 [/imath]
[imath] N' = (1 - \alpha) \, \mathrm{R}_4 \, + \, \frac{ \alpha \, \mathrm{R}_4 \, \cdot \, \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 } [/imath]
[imath] N' = [ (1 - \alpha) \, + \, \frac{ \alpha \, \cdot \, \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 } ] \cdot \mathrm{R}_4 [/imath]
[imath] N' = ( (1 - \alpha) \cdot ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 ) \, + \, \alpha \cdot \, \mathrm{R}_5 ) \cdot \frac{\mathrm{R}_4}{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 }[/imath]
[imath] N' = ( ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 ) - ( \alpha^2 \, \mathrm{R}_4 \, + \, \alpha \cdot \mathrm{R}_5 ) \, + \, \alpha \cdot \, \mathrm{R}_5 ) \cdot \frac{\mathrm{R}_4}{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 }[/imath]
[imath] N' = ( \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 ) \cdot \frac{\mathrm{R}_4}{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 } \,\,\,\,\,\,\,\, (12) [/imath]
Zodat:
[imath] W = \frac{ \alpha \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot V \,\,\,\,\,\,\,\, (13) [/imath]
Combinatie van (9) en (13) geeft:
[imath] W = \frac{ \alpha \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot \frac{\alpha \, \mathrm{R}_7}{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 \, - \, \alpha^2 \, \mathrm{R}_3 } \cdot U \,\,\,\,\,\,\,\, (14) [/imath]
Tenslotte zien we dat:
[imath] U_{uit} = - W \,\,\,\,\,\,\,\, (15) [/imath]
Combinatie van (1), (14) en (15) levert:
[imath] U_{uit} = \frac{ \alpha \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot \frac{\alpha \, \mathrm{R}_7}{ \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 \, - \, \alpha^2 \, \mathrm{R}_3 } \cdot \frac{ \mathrm{R}_2 }{ \mathrm{R}_1 } \cdot U_{in} [/imath]
[imath] U_{uit} = \frac{ \alpha \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot \frac{(\alpha \, \mathrm{R}_4 + \mathrm{R}_5) \cdot ( \alpha \, \mathrm{R}_7) }{ ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot ( \alpha \, \mathrm{R}_3 \, + \, \mathrm{R}_7 \, - \, \alpha^2 \, \mathrm{R}_3) } \cdot \frac{ \mathrm{R}_2 }{ \mathrm{R}_1 } \cdot U_{in} [/imath]
[imath] U_{uit} = \frac{ \alpha \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot \frac{(\alpha \, \mathrm{R}_4 + \mathrm{R}_5) \cdot ( \alpha \, \mathrm{R}_7) }{ ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot ( \alpha \, \mathrm{R}_3) \, + \, ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot \mathrm{R}_7 \, - \, ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot\alpha^2 \, \mathrm{R}_3 } \cdot \frac{ \mathrm{R}_2 }{ \mathrm{R}_1 } \cdot U_{in} [/imath]
[imath] U_{uit} = \frac{ \alpha^2 \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot \frac{(\alpha \, \mathrm{R}_4 + \mathrm{R}_5) \cdot \mathrm{R}_7 }{ ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot ( \alpha \, \mathrm{R}_3) \, + \, ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot \mathrm{R}_7 \, - \, ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot\alpha^2 \, \mathrm{R}_3 } \cdot \frac{ \mathrm{R}_2 }{ \mathrm{R}_1 } \cdot U_{in} \,\,\,\,\,\,\,\, (16) [/imath]
Substitutie van (5) in (16) geeft:
[imath] U_{uit} = \frac{ \alpha^2 \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot \frac{\alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 }{ ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot ( \alpha \, \mathrm{R}_3) \, + \, \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 \, - \, ( \alpha \, \mathrm{R}_4 + \mathrm{R}_5 ) \cdot\alpha^2 \, \mathrm{R}_3 } \cdot \frac{ \mathrm{R}_2 }{ \mathrm{R}_1 } \cdot U_{in} [/imath]
[imath] U_{uit} = \frac{ \alpha^2 \mathrm{R}_5 }{ \alpha \, \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 } \cdot \frac{\alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 }{ \alpha^2 \, \mathrm{R}_3 \, \mathrm{R}_4 + \alpha \, \mathrm{R}_3 \, \mathrm{R}_5 \, + \, \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 \, - \, \alpha^3 \, \mathrm{R}_3 \, \mathrm{R}_4 - \alpha^2 \, \mathrm{R}_3 \, \mathrm{R}_5 } \cdot \frac{ \mathrm{R}_2 }{ \mathrm{R}_1 } \cdot U_{in} [/imath]
[imath] U_{uit} = \frac{ \alpha^2 \mathrm{R}_2 \mathrm{R}_5 \, ( \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 ) }{ \mathrm{R}_1 ( \alpha \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 ) \, ( \alpha^2 \, \mathrm{R}_3 \, \mathrm{R}_4 + \alpha \, \mathrm{R}_3 \, \mathrm{R}_5 \, + \, \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 \, - \, \alpha^3 \, \mathrm{R}_3 \, \mathrm{R}_4 - \alpha^2 \, \mathrm{R}_3 \, \mathrm{R}_5 ) } \cdot U_{in} \,\,\,\,\,\,\,\, (17) [/imath]
De functie [imath] \mathrm{gn}( \,\, ) [/imath] uit het blok schema (zie vorige berichtje) luidt dus als volgt:
[imath] \mathrm{gn}(\alpha) = \frac{ \alpha^2 \mathrm{R}_2 \mathrm{R}_5 \, ( \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 ) }{ \mathrm{R}_1 ( \alpha \mathrm{R}_4 \, + \, \mathrm{R}_5 - \alpha^2 \, \mathrm{R}_4 ) \, ( \alpha^2 \, \mathrm{R}_3 \, \mathrm{R}_4 + \alpha \, \mathrm{R}_3 \, \mathrm{R}_5 \, + \, \alpha \, \mathrm{R}_4^2 \, + \, \mathrm{R}_ 4 \, \mathrm{R}_5 \, - \, \alpha^2 \, \mathrm{R}_4^2 \, - \, \alpha^3 \, \mathrm{R}_3 \, \mathrm{R}_4 - \alpha^2 \, \mathrm{R}_3 \, \mathrm{R}_5 ) } \,\,\,\,\,\,\,\, (18) [/imath]
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