Midian Electronics BTD-1A, Руководство пользователя

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HARDWARE ALIGNMENT
The frequency of the BTD-1 is set using one of two methods:
Method 1
Install JU1 and, while monitoring Pin 7 of U1C with a frequency counter, adjust R15 to the desired frequency.
Remove JU1.
Method 2
Inject an audio signal, at the proper amplitude, on the desired burst tone frequency into the orange lead. While
observing Pin 7 of U1C with a scope, adjust R15 for a peak in amplitude.
The Bandwidth is set by injecting the signal into the orange lead, as above, except set the frequency .25% away
from the desired burst tone frequency. While monitoring Pin 7 of U2B, adjust R25 until Pin 7 goes high.
R34 adjusts the tone decode time before actuation of any of the BTD-1 outputs. (This delay is used to prevent
falsing due to short duration audio signals entering the decoder.)
R11 adjusts the amount of negative or positive squelch input voltage that is required to disable the repeater
output lead when the carrier is no longer present. Most newer radios use TTL 5 volt logic levels but a lot of older
radios may only change a few tenths of a volt. Set R11 for your particular circumstance.
U3F with R19 and C6 acts as a hang timer after the loss of carrier signal on Pin 7 yellow squelch lead. When this
timer times out it causes U3 to generate a reset pulse on U2C turning off the repeater output.
Continuous Decode
The BTD-1 has the trace IC2 pin 14 to R37 cut with a jumper from IC2 pin 7 to R37 installed. As long as the BTD-
1 receives a continuously programmed tone the unit will turn on the Repeater Out transistor causing its output to
go low (brown wire).