tcm3105 ETC-unknow, tcm3105 Datasheet - Page 7

• Manufacturer Part Number: tcm3105
• Description: Fsk Modem
• Manufacturer: ETC-unknow

carrier detect
control and timing
transmit and receive modes
The carrier-detect circuits comprise an energy detector and digital delay. The energy detector compares the
total signal level at the output of the receive filter to an externally set threshold level on the CDL input. The
comparator has a 2.5-dB hysteresis and a delay to allow for momentary signal loss and to prevent oscillation.
The output detector is available on CDT where a high level indicates that a carrier is present. The data output
is clamped to a mark condition when the carrier-detect output switches off at the end of transmission.
An on-chip oscillator runs from an external 4.4336-MHz crystal connected between OSC1 and OSC2 or an
external signal driving OSC1. A clock signal equal to 16 times the highest selected bit rate (transmit or receive)
is available on the CLK output.
The single-supply rail means that all analog functions are referenced to an internally generated reference. All
analog inputs and outputs must be ac coupled.
The various modes of operation of the TCM3105 are given in Table 1. The data convention is that a logic high
is a mark and a logic low is a space.
POST OFFICE BOX 1443
POST OFFICE BOX 655303
HOUSTON, TEXAS 77251–1443
DALLAS, TEXAS 75265
TCM3105DWL, TCM3105JE, TCM3105JL
SCTS019C – NOVEMBER 1985 – REVISED MAY 1994
TCM3105NE, TCM3105NL
FSK MODEM
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