Telex VEGA C-5110B, Instruction Manual, Page: 18 / 46

Main PCB Transmit Circuits
During mic-PTT or intercom, the audio signal
path is from a from a mic input such as the desk
mic through C2, U1-2,1, and C50 to the TX
compressor input at U24A-2. This circuit is
identical to the selected RX compressor
previously described. TX compressor output at
U24-7 is applied to the TX notch filter U28
through U16-11,10. TX notch filter U28 is
identical in circuit and operation to the selected
RX filter previously described. The TX signal
path from the TX notch output to the
upper-PCB TX circuit is through U9-8,9, R37,
U15-6,7, and P5-1. Analog gates U16-11,10
and U9-8,9 are enabled only during PTT or
intercom.
If a DTMF or paging-encoder option is
installed, connection is made to P13-1,2,3,4,5,6
on main PCB.
Alert-Tone Generator
Alert-switch operation enables PTT and the
1-kHz sinewave oscillator U27-8,9,10. This
oscillator consists of a multiple-feedback
bandpass filter with a Q of about 7.5 and, when
enabled, a positive-feedback path to cause
oscillation. When U26-13 is high, the
positive-feedback path is from U27-8 through
R89, U26-2,1, and R74. When oscillation
amplitude reaches the threshold of diode CR18
and CR22 conduction, loop gain is decreased
and oscillation amplitude is stable at a level
lower than U27-8 clipping.
Technical Assistance
Vega products are engineered to meet your
requirements of performance, reliability, and
compatibility. Technical assistance is offered
by correspondence or telephone, should it be
required, to assure your satisfaction.
Warranty (Limited)
All Vega signaling products are guaranteed
against malfunction due to defects in materials
and workmanship for three years, beginning at
the date of original purchase. If such a
malfunction occurs, the product will be
repaired or replaced (at our option) without
charge during the three-year period, if delivered
to the Vega factory. Warranty does not extend
to damage due to improper repairs, finish or
appearance items, or malfunction due to abuse
or operation under other than the specified
conditions, nor does it extend to incidental or
consequential damages. Some states do not
allow the exclusion or limitation of incidental
or consequential damages, so the above
limitation may not apply to you. This warranty
gives the customer specific legal rights, and
there may be other rights which vary from state
to state.
Claims
No liability will be accepted for damages
directly or indirectly arising from the use of our
materials or from any other causes. Our liability
shall be expressly limited to replacement or
repair of defective materials.
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