Broadcast Electronics AM-2.5E, User Manual

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WARNING: DISCONNECT POWER PRIOR TO SERVICING
2-4
2-25.
FWD AND RFL CALIBRATIONS.
FWD CAL control R56 and RFL CAL control R143
calibrate the transmitter forward and reflected power samples. Due to the critical nature
of the FWD CAL and RFL CAL controls, the controls are not considered field adjustable.
If the controls are required to be adjusted, contact the Broadcast Electronics Customer
Service Department for information and instructions to adjust the FWD and RFL CAL
controls.
2-26.
STEREO CIRCUIT BOARD ADJUSTMENTS.
2-27.
STEREO ADJUSTMENT.
The stereo adjustment consists of configuring the equalization
circuitry on the stereo circuit board to obtain the optimum stereo performance. The
equalization circuitry consists of the equalization circuit 1 and equalization circuit 2
controls. A complete description of the procedure to adjust the equalization controls is
presented in SECTION II, INSTALLATION. Refer to STEREO ADJUSTMENT in
SECTION II for the adjustment procedure.
2-28.
EXCITER CIRCUIT BOARD ADJUSTMENTS.
2-29.
MODULATION CALIBRATION.
Modulation calibration control R62 calibrates the exciter
modulation circuit. Due to the critical nature of the modulation calibration control, the
control is not considered field adjustable. If the control is to be adjusted, contact the
Broadcast Electronics Customer Service Department for information and instructions to
adjust the modulation calibration control.
2-30.
PHASE MODULATOR CALIBRATION.
Phase modulator calibration control R159
calibrates the exciter phase modulator circuit. Due to the critical nature of the phase
modulator calibration control, the control is not considered field adjustable. If the control
is to be adjusted, contact the Broadcast Electronics Customer Service Department for
information and instructions to adjust the phase modulator calibration control.
2-31.
SYMMETRY CONTROL.
Symmetry calibration control R170 adjusts the exciter RF
output square-wave signal. Due to the critical nature of the symmetry control, the
control is not considered field adjustable. If the control is to be adjusted, contact the
Broadcast Electronics Customer Service Department for information and instructions to
adjust the symmetry control.
2-32.
IPM CORRECTION CIRCUIT CONTROLS.
IPM GAIN control R189, IPM TRACK control
R104, IPM SHAPE CONTROL R198, and IPM ZERO SET control R191 calibrate the IPM
correction circuit. Due to the critical nature of the IPM correction circuit controls, the
controls are not considered field adjustable. If the controls are to be adjusted, contact the
Broadcast Electronics Customer Service Department for information and instructions to
adjust the IPM correction circuit controls.
2-33.
SINGLE CHAN MONO LEVEL CONTROL.
SINGLE CHAN MONO LEVEL control R41
is designed to boost a remaining audio channel level in the event of a failure in one
channel. A complete description of the procedure to adjust the SINGLE CHAN MONO
LEVEL control is presented in SECTION II, INSTALLATION. Refer to SINGLE
CHANNEL LEVEL in SECTION II for the adjustment procedure.
2-34.
AVERAGE MODULATION LIMIT CONTROL.
Average modulation limit control R217
limits the average tone modulation. The control is adjusted to limit at 110% tone
modulation. Due to the critical nature of the modulation calibration control, the control is
not considered field adjustable. If the control is to be adjusted, contact the Broadcast
Electronics Customer Service Department for information and instructions to adjust the
average modulation limit control.
2-35.
NEG LIMIT CONTROL.
NEG LIMIT control R76 limits the negative L+R information to
prevent excessive modulation when the L+R signal is summed with the pilot tone. The
NEG LIMIT control is adjusted in the following procedure.