ACCURATE ELECTRONICS 104001C Manuale - Pagina 3

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ACCURATE ELECTRONICS INC
WWW.ACCURATE.ORG
PO BOX 1654 97075-1654 8687 SW HALL BLVD 97008
TABLE 1. Typical Transmit and Receive Equalization Frequency Response
Receive
Equalizer
300Hz
400Hz
Switch
Setting
(dB)
0
0.0
0.5
-0.23
1.0
-0.52
1.5
-0.75
2.0
-1.00
2.5
-1.22
3.0
-1.50
3.5
-1.71
4.0
-2.02
4.5
-2.25
5.0
-2.49
5.5
-2.68
6.0
-2.89
6.5
-3.07
7.0
-3.29
7.5
-3.45
switch. The precise amount of gain or loss required in the channel is then
selected in 0.1dB increments, via an eight-position front-panel DIP switch.
Amplitude Equalization
2.05 The 104001C's active slope-type amplitude equalizers allow from 0 to
7.5dB of prescription-set gain at 2804Hz (re 1004Hz) to be introduced into
the module's receive and transmit channels individually. Adjustable in 0.5dB
increments via front-panel DIP switches, this type of equalization is ideal for
nonloaded cable and can also be used effectively in many loaded-cable
applications to compensate for the frequency-response characteristics of
metallic facilities interfacing the module. The equalized gain response of
each module is not affected by flat gain or loss adjustments, which are used
to provide precise transmission alignment. The frequency response of the
equalizers is shown in tabular format in Table 1.
Note: Because introduction of equalization into either channel of the
104001C does not affect 1004Hz levels, equalization can be introduced not
only before but after transmission levels are set.
2.06 Whether one or both channels' equalizers are used depends upon the
104001C's position in the circuit. Use of the module as an amplifier at an
intermediate point in a 4wire circuit, for example, often requires the use of
the transmit equalizer as well as the receive equalizer. In any case, equalizing
at the receive end of a circuit (post-equalization) is generally preferable to
equalizing at the transmit end (pre-equalization). Pre-equalization tends to
amplify high-frequency signals to a level that is conducive to crosstalk. Post-
equalization not only eliminates this problem but also expedites the
equalization process because the circuit is easier to equalize at the receive
end. In some applications, however, pre-equalization may be necessary
because post-equalization at the receive end is unavailable.
Impedance Matching
2.07 Impedance-matching transformers at all four ports of the 104001C can
be switch-optioned for balanced 1200, 600, or 150-ohm terminating
impedance. A single option switch selects the desired impedance for both
facility-side ports (receive input and transmit output); a second option switch
performs this function for both terminal-side ports (receive output and
transmit input). Thus, on both the facility and terminal sides, the 104001C
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Equalized Gain (dB) Introduced at Various Frequencies
500Hz
800Hz
0.0
0.0
0.0
-0.19
-0.15
-0.06
-0.42
-0.33
-0.13
-0.60
-0.49
-0.18
-0.80
-0.64
-0.24
-0.98
-0.78
-0.29
-1.20
-0.95
-0.36
-1.37
-1.09
-0.41
-1.63
-1.29
-0.49
-1.79
-1.42
-0.53
-1.98
-1.57
-0.59
-2.14
-1.69
-0.63
-2.30
-1.81
-0.68
-2.44
-1.93
-0.72
-2.61
-2.05
-0.76
-2.74
-2.15
-0.78
Practice Section 104001C Rev B
BEAVERTON OR USA 503.641.0118
1004Hz
1500Hz
1800Hz
0.0
0.0
0.0
0.0
+0.15
+0.43
0.0
+0.32
+0.93
0.0
+0.46
+1.33
0.0
+0.61
+1.76
0.0
+0.75
+2.15
0.0
+0.90
+2.60
0.0
+1.03
+2.97
0.0
+1.22
+3.54
0.0
+1.33
+3.90
0.0
+1.47
+4.32
0.0
+1.58
+4.67
0.0
+1.69
+5.05
0.0
+1.79
+5.38
0.0
+1.89
+5.76
0.0
+1.98
+6.06
can interface a variety of facilities and equipment, as listed in Table 2. The
150-ohm options provide a small amount of slope equalization for long
sections of non-loaded cable through the deliberate impedance mismatch.
TABLE 2. Terminating Impedance Selection Guidelines.
Impedance
1200 ohms
Loaded Cable
600 ohms
Non-loaded cable, carrier, SF and DX signaling
units, terminating sets, station apparatus.
Sealing Current and Simplex Leads
2.08 The 104001C contains two separate and independent 25mA sealing-
current sources, one on the facility side and one on the terminal side of the
module. In addition, all four impedance-matching transformers on the
104001C are center-tapped to derive balanced simplex (SX) leads. Option
switches on the facility and terminal sides of the module afford a choice of
four sealing-current and simplex-lead options, as follows:
2.09 When the 104001C's internal sealing-current option on the facility side
is selected, 25mA of sealing current flows from the transmit output port (pins
41 and 47) and returns via the receive input port (pins 7 and 13). When the
4001C's internal sealing-current option on the terminal side is selected,
25mA of sealing current flows from the transmit input port (pins 55 and 49)
and returns via the receive output port (pins 5 and 15). Both sealing-current
sources have a ZAP feature that provides a greater amount of current for a
few seconds when power is initially applied to the module. Each of the two
front-panel "SEAL CURR" LEDs lights when its respective source is active
and current is flowing.
2.10 A second sealing-current/simplex-lead option available independently
on the facility and terminal sides of the 104001C excludes the module's
sealing-current sources from the circuit and provides return paths for sealing
current applied at the distant end of the facilities.
2.11 A third option is the derivation of normal simplex leads on either or
both sides of the module. This allows the 104001C to be used on circuits
January 2014
FAX 503.646.3903
2500Hz
2804Hz
0.0
0.0
+0.43
+0.50
+0.93
+1.07
+1.33
+1.54
+1.76
+2.04
+2.15
+2.49
+2.60
+3.01
+2.97
+3.45
+3.54
+4.12
+3.90
+4.56
+4.32
+5.08
+4.67
+5.51
+5.05
+5.99
+5.38
+6.41
+5.76
+6.90
+6.06
+7.30
Facility or Equipment Guidelines
3