Midian Electronics BTD-1A, Руководство пользователя

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CIRCUIT DESCRIPTION
The single tone is input on the orange lead and passes through C1 to the input of U1A, which amplifies the input
tone. R4 may be adjusted to change the sensitivity of the unit. The tone then passes through R5 to the active
filter circuit of U1B, U1C, and U1D. The output on Pin 7 of U1C is passed through R22 to detector U2A. The
output of U2A passes through D4 and R30 to the input of comparator U2B. The comparator's window is set by
adjusting R25 (bandwidth) to produce the proper trigger voltage on U2B, Pin 6.
R34, when adjusted, provides a variable delay from the moment of decode to the time the various outputs are
activated. The output of U2B, Pin 7 goes high when the proper burst tone is detected, and D3A is then back
biased. C13 then charges, triggering U3A. The output of U3A goes low, producing a pulse through C14, turning
off U3B for four seconds, and producing a high on its output.
The high output on U3B turns on Q1 for four seconds, causing a low output on the grey/white Pin 10 horn output
wire. When U3A triggers, a 2400 Hz alert tone is produced on the blue lead, Pin 5, and violet lead, Pin 13, and
after 2 seconds, a low transpond output is produced on the green lead, Pin 1, for approximately 2 seconds.
The high output of U3B is also passed to the input of latch U2C. U2C turns on, producing a high output that turns
on Q3, which creates a low call light output on the white lead, Pin 9, & back biases D8, producing a float output on
the normally high green/white lead positive squelch output via JU3.
A high input on the orange/white monitor 1 input lead, Pin 12, latches U2C. The monitor 2 input on the grey lead,
Pin 11, is normally grounded, through JU2. If JU2 (ground) is removed, a transition from a low to a high or float
on the monitor 2 input lead produces monitoring. When the input returns to low, the white call light lead, Pin 9,
the brown repeater out lead, Pin 3, and the green/white radio squelch lead, Pin 8, are reset.
The negative and positive squelch inputs are used if the BTD-1 is to be used in a radio repeater. The transition
from a low on the yellow lead, Pin 7, via JU6 for the negative squelch input or a high on the yellow lead via JU5
for the positive squelch polarity, or a float, will turn off Q4, and the brown repeater output lead, Pin 3, will float.
The white call light lead, Pin 9, and the green/white squelch output lead, Pin 8, will also reset.
MIDIAN CONTACT INFORMATION
MIDIAN ELECTRONICS, INC.
2302 East 22
nd
Street
Tucson, Arizona 85713 USA
Toll-Free: 1-800-MIDIANS
Main: 520-884-7981
E-mail: sales@midians.com
Web: www.midians.com