Detector - Bang & Olufsen beomaster 2000 Service Manual

5-3
Bang&Olufr
Detelrtor
Detector
For at der kan foretages en korrektjustering af detek-
Equipment needed to enable correct adjustrnent of the
torerl skal der bl.a. anvendes et forvrangningsmeter
detector includes a distortion meter as explained in
som beskrevet i punlt 1. Hvis et forwengningsmeter
point 1. Should a distortion meter not be at hand it is
ikke er tilgangeligt, kan der foretages en tilnermet
possible to make an approximated adjustrnent as
justering som beskrevet i punkt 2.
1. Modtageren indstilles pi f.eks. 94 MHz.
En kombineret milesender og sweepgenerator til-
sluttes antenneindgange& og indstilles til at afgive
1 mV. A +75 ktrlz.
Oscilloskop tilsluttes i l'tP2.
Milesenderens frekvens indstilles til 94 MHz, og
finindstilles til minimum 2. harmonisk af sigrnlet
(se fig.).
Et forwangningsmeter tilsluttes hojttalerudgangen
Et DC voltneter tilsluttes imellem 1TP3 & 1TP4.
Med 1L11justeres, indtil der miles minimum for-
wangning. Derefter justeres med 1L10, indtil der
mdles 0V.
Gentag begge justeringer, indtil de er i orden
RIGTIG
CORRECT
FORKERT
INCORRECT
explained in point 2.
1. Set the receiver at say, 94 MHz.
Connect a combination signal generator/sweep
generator to the aerial input and set it to yield
1 mV EMF, L+75 WIz.
Connect an oscilloscope to 1TP2.
Set the signal generator frequency at 94 MHz and
trim it to minimum the 2nd harmonic of the signal
(see fig.).
Connect a distortion meter to the loudspeaker
ouDuL
Connect a DC volftneter between 1TP3 & 1TP4.
Adjust with 1L11 until minimum distortion is
obtained- Nexl adjust with 1L10 until a reading of
0V is obtained.
Repeat both these adjustrnents until they are OK.
A A / \ A
/"!"'v^1
Justeringen foretages ved hjalp af "S-kurve"; men
der vil vere usikkerhed for, hvorvidt modfageren
overholder sine forvrengningsdata.
Modtageren indstilles pA f.eks. 94 MHz.
En kombineret milesender og sweepgenerator til-
sluttes antenneindgangen, og indstilles til at afgive
1 mV EMF, L +75 ktrlz.
Oscilloskopet tilsluttes i ITP?.
MAlesenderens frekvens indstilles til 94 MHz, og
finindstilles til minimum 2. harmonisk af signalet
(se fig).
Generatoren indstilles til sweep.
Et oscilloskop tilsluttes 1TP5 og et DC voltneter
tilsluttes mellem 1TP3 & 1TP4.
Med 1L10 & ll.ll justeres til maksimum og
symmetrisk S-kurve.
Derefter justeres med 1L10 indtil der miles 0V.
2. Make the adjustrnents by means of a "S-curve", but
it will be uncertain whether the receiver maintains
its distortion specifications.
Set the receiver at say, 94 MHz.
Connect a combination signal generator/sweep
generator to the aerial input and set it to yield
1 mV EMF, L +75 ktlz.
Connect an oscilloscope to 1TP2.
Set the signal generator frequency at g4 MHz and
trim it to minimum the 2nd harmonic of the signal
(see fig).
Set the generator to sweep.
Connect an oscilloscope to 1TP5 and connect a DC
voltrneter between 1TP3 & 1TP4.
Adjust with 1L10 & 1L11 to maximum and symme-
trical S-curve.
Next adjust with 1L10 until a reading of 0V is
obtained