![Tait T850 II Series Скачать руководство пользователя страница 52](http://html1.mh-extra.com/html/tait/t850-ii-series/t850-ii-series_service-manual_3314083052.webp)
B2.12
T855 Circuit Operation
Copyright TEL
2.12
Received Signal Strength Indicator (RSSI)
(Refer to the T800-04-0000 RSSI PCB circuit diagram in Section 6.2 and the IF section cir-
cuit diagram (sheet 3) in Section 6.3.)
The RSSI option PCB plugs directly into the main PCB (support circuitry being fitted as
standard). It is fitted to the T855 whenever receiver signal strength monitoring is
required, e.g. trunking or voting. Its function is to provide a DC voltage proportional to
the signal level at the receiver input. The DC voltage is available at D-range 1 (PL100
pin 5).
The RSSI also provides the capability for high level signal strength muting, which may
be selected on PL250 (refer to Section 3.5). The mute threshold may be set between
-115dBm and -70dBm by RV235.
Figure 2.7 T855 RSSI Block Diagram (T800-04-0000 RSSI PCB)
The variable gain stage (Q1A) is a common emitter amplifier with its emitter grounded
and the AGC control loop voltage applied to its base. Since the AGC loop will maintain
a constant signal level at the collector, the gain of Q1 must be proportional to the incom-
ing 455kHz signal level. The gain of Q1 is linearly proportional to its collector current
which itself is exponentially related to the base-emitter voltage. Thus there is a logarith-
mic relationship between the base-emitter voltage and the gain. The circuit therefore
produces a feedback voltage, and an output voltage, logarithmically related to the RF
input signal.
The AGC loop is followed by a DC amplifier which provides level shifting, temperature
compensation and gain to give a nominal 1V/10dB at the RSSI output. RV320 on the
main PCB is used to set the RSSI voltage to a fixed value at a given RF input signal
strength.
+V
Amp
Detector
Error Amp
Q1C
Q1A &
Q1B
VDC
Variable
Gain Stage
Q1E
RSSI
Input
Temp Comp
NTC
DC Amp
(Gain= x33)
Temp
Comp
Q1D
DC Offset
(Ref)
RSSI Output
1V/10dB
Содержание T850 II Series
Страница 12: ...12 M850 00 31 09 98 Copyright TEL...
Страница 14: ...AII M850 00 31 09 98 Copyright TEL...
Страница 20: ...A2 4 Mechanical M850 00 31 09 98 Copyright TEL...
Страница 26: ...BII M850 00 31 09 98 Copyright TEL...
Страница 28: ...B1 2 T855 General Information M850 00 31 09 98 Copyright TEL...
Страница 29: ...M850 00 T855 General Information B1 3 Copyright TEL 31 09 98 replace A4 pages B1 3 B1 4 with A3 pages B1 3 B1 4...
Страница 30: ...B1 4 T855 General Information M850 00 31 09 98 Copyright TEL replace A4 pages B1 3 B1 4 with A3 pages B1 3 B1 4...
Страница 40: ...B1 14 T855 General Information M850 00 31 09 98 Copyright TEL...
Страница 42: ...B2 2 T855 Circuit Operation M850 00 31 09 98 Copyright TEL...
Страница 68: ...B4 2 T855 Functional Testing M850 00 31 09 98 Copyright TEL...
Страница 74: ...B4 8 T855 Functional Testing M850 00 31 09 98 Copyright TEL...
Страница 94: ...B5 20 T855 Fault Finding M850 00 31 09 98 Copyright TEL...
Страница 96: ...B6 1 2 T855 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 102: ...B6 2 2 T800 04 0000 RSSI PCB Information M850 00 31 09 98 Copyright TEL...
Страница 108: ...B6 3 2 T855 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 115: ...IPN 220 01396 02 M850 00 T855 PCB Information B6 3 9 Copyright TEL 31 09 98...
Страница 122: ...IPN 220 01396 02 B6 3 16 T855 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 124: ...CII M850 00 31 09 98 Copyright TEL...
Страница 126: ...C1 2 T856 857 General Information M850 00 31 09 98 Copyright TEL...
Страница 127: ...M850 00 T856 857 General Information C1 3 Copyright TEL 31 09 98 replace A4 pages C1 3 C1 4 with A3 pages C1 3 C1 4...
Страница 128: ...C1 4 T856 857 General Information M850 00 31 09 98 Copyright TEL replace A4 pages C1 3 C1 4 with A3 pages C1 3 C1 4...
Страница 129: ...M850 00 T856 857 General Information C1 5 Copyright TEL 31 09 98 replace A4 pages C1 5 C1 6 with A3 pages C1 5 C1 6...
Страница 130: ...C1 6 T856 857 General Information M850 00 31 09 98 Copyright TEL replace A4 pages C1 5 C1 6 with A3 pages C1 5 C1 6...
Страница 140: ...C1 16 T856 857 General Information M850 00 31 09 98 Copyright TEL...
Страница 154: ...C2 14 T856 857 Circuit Operation M850 00 31 09 98 Copyright TEL...
Страница 170: ...C4 2 T856 857 Functional Testing M850 00 31 09 98 Copyright TEL...
Страница 176: ...C4 8 T856 857 Functional Testing M850 00 31 09 98 Copyright TEL...
Страница 198: ...C6 1 2 T856 857 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 204: ...C6 2 2 T856 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 220: ...C6 3 2 T857 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 227: ...M850 00 T857 PCB Information C6 3 9 Copyright TEL 31 09 98 replace A4 pages C6 3 9 C6 3 10 with A3 pages C6 3 9 C6 3 10...
Страница 228: ...C6 3 10 T857 PCB Information M850 00 31 09 98 Copyright TEL replace A4 pages C6 3 9 C6 3 10 with A3 pages C6 3 9 C6 3 10...
Страница 232: ...IPN 220 01398 02 C6 3 14 T857 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 234: ...DII M850 00 31 09 98 Copyright TEL...
Страница 236: ...D1 2 T858 859 General Information M850 00 31 09 98 Copyright TEL...
Страница 237: ...M850 00 T858 859 General Information D1 3 Copyright TEL 31 09 98 replace A4 pages D1 3 D1 4 with A3 pages D1 3 D1 4...
Страница 238: ...D1 4 T858 859 General Information M850 00 31 09 98 Copyright TEL replace A4 pages D1 3 D1 4 with A3 pages D1 3 D1 4...
Страница 239: ...M850 00 T858 859 General Information D1 5 Copyright TEL 31 09 98 replace A4 pages D1 5 D1 6 with A3 pages D1 5 D1 6...
Страница 240: ...D1 6 T858 859 General Information M850 00 31 09 98 Copyright TEL replace A4 pages D1 5 D1 6 with A3 pages D1 5 D1 6...
Страница 248: ...D2 2 T858 859 Circuit Operation M850 00 31 09 98 Copyright TEL...
Страница 256: ...D3 2 T858 859 Initial Adjustment M850 00 31 09 98 Copyright TEL...
Страница 264: ...D3 10 T858 859 Initial Adjustment M850 00 31 09 98 Copyright TEL...
Страница 266: ...D4 2 T858 859 Fault Finding M850 00 31 09 98 Copyright TEL...
Страница 270: ...D4 6 T858 859 Fault Finding M850 00 31 09 98 Copyright TEL replace A4 pages D4 5 D4 6 with A3 pages D4 5 D4 6...
Страница 282: ...D5 1 2 T858 859 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 288: ...D5 2 2 T858 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 293: ...IPN 220 01141 01 M850 00 T858 PCB Information D5 2 7 Copyright TEL 31 09 98...
Страница 298: ...IPN 220 01141 01 D5 2 12 T858 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 300: ...D5 3 2 T859 PCB Information M850 00 31 09 98 Copyright TEL...
Страница 305: ...IPN 220 01159 01 M850 00 T859 PCB Information D5 3 7 Copyright TEL 31 09 98...
Страница 312: ...EII M850 00 31 09 98 Copyright TEL...
Страница 316: ...E2 2 T850 VCO PCB Information M850 00 31 09 98 Copyright TEL...
Страница 319: ...T850 VCO PCB IPN 220 01145 02 Bottom Side Copyright TEL 31 09 98 IPN 220 01145 02 M850 00 T850 VCO PCB Information E2 5...
Страница 320: ...IPN 220 01145 02 E2 6 T850 VCO PCB Information M850 00 31 09 98 Copyright TEL T850 VCO PCB IPN 220 01145 02 Top Side...
Страница 328: ...G1 4 T855 Link Selectable Features M850 00 31 09 98 Copyright TEL...
Страница 332: ...G2 4 T856 857 Optional Features M850 00 31 09 98 Copyright TEL...
Страница 334: ...G3 2 Talk Through Repeater M850 00 31 09 98 Copyright TEL...
Страница 340: ...HII M850 00 31 09 98 Copyright TEL...
Страница 356: ...I II M850 00 31 09 98 Copyright TEL...
Страница 358: ...I1 2 Tools Required M850 00 31 09 98 Copyright TEL...
Страница 366: ...I2 8 T855 856 857 SII SI Conversion M850 00 31 09 98 Copyright TEL...
Страница 370: ...I3 4 T858 859 SII SI Conversion M850 00 31 09 98 Copyright TEL...