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                22.1    PATTERN MODEMS . . . . . . . . . . . . . . . . .  22-1
                22.1.1    Data Transmitter . . . . . . . . . . . . . . .  22-1
                22.1.2    Data Receiver  . . . . . . . . . . . . . . . .  22-2
                22.2    DRAWING PACKAGE NUMBERS  . . . . . . . . . . . .  22-3
                22.3    RESPONSIBLE ENGINEER . . . . . . . . . . . . . .  22-3

                                      CHAPTER 22
                                        MODEMS

        22.1  PATTERN MODEMS


        22.1.1  Data Transmitter

          This is the modem used in the CAT, and it is primarily used for
        distributing beam code information from the Master Pattern Generator
        (MPG) micro to the CAR modules associated with each linac sector micro.
        SPECIFICATION.
        Carrier Frequency:      83.25, 89.25, 95.25, 101.25,107.25,113.25 MHz
                                crystal controlled.
        Output level:           +30 to +50 dBmV adjustable.
        Power requirements:     12 +/- 0.25 VDC at 0.9 A.
        Operating temperature:  50 to 100 degrees F.
        Data circuit interface: Subset of RS449.
        Connections:            DCE (including power) 37 pin "D" connector.
                                PIN  FUNCTION    PIN  FUNCTION    PIN  FUNCTION
                                  1  --------      2  --------      3  +12V
                                  4  TxD+          5  --------      6  --------
                                  7  RTS+          8  --------      9  CTS+
                                 10  --------     11  --------     12  --------
                                 13  --------     14  +12V         15  --------
                                 16  +12V         17  +12V         18  --------
                                 19  GROUND       20  GROUND       21  GROUND
                                 22  TxD-         23  --------     24  --------
                                 25  RTS-         26  --------     27  CTS-
                                 28  --------     29  --------     30  --------
                                 31  --------     32  GROUND       33  --------
                                 34  GROUND       35  GROUND       36  --------
                                 37  --------
                                "F" fitting for RF cable connection.
                          Special cables, detailed in the CAT drawing package,
                          connect the CAT PCB and front panel to the modem.



        MODEMS                                                       Page 22-2

        Spectra:                To perform without interference to adjacent TV
                                signals by being at least 50 dB down from
                                carrier level at channel edges.
        Latency:                RTS - CTS delay = 200 msec.

        22.1.2  Data Receiver

          This is the modem used in the CAR, and it is primarily used for
        receiving beam code information transmitted by the CAT in the Master
        Pattern Generator (MPG) micro.
        SPECIFICATION
        Receiver frequency:     241.25, 247.25, 253.25, 259.25, 265.25, 271.25 MHz
                                crystal controlled.
        Input level:            -10 to +20 dBmV (+6 optimum).
        Power requirements:     12 to +/- 0.25 VDC @ 0.9 A.
        Operating temperature:  50 to 100 degrees F.
        Data circuit interface: Subset of RS449.
        Connections:            DCE (including power) 37 pin "D" connector.
                                PIN  FUNCTION    PIN  FUNCTION    PIN  FUNCTION
                                  1  --------      2  --------      3  +12V
                                  4  --------      5  --------      6  RxD+
                                  7  --------      8  --------      9  --------
                                 10  --------     11  --------     12  --------
                                 13  CD+          14  +12V         15  --------
                                 16  +12V         17  +12V         18  --------
                                 19  GROUND       20  GROUND       21  GROUND
                                 22  --------     23  --------     24  RxD-
                                 25  --------     26  --------     27  --------
                                 28  --------     29  --------     30  --------
                                 31  CD-          32  GROUND       33  --------
                                 34  GROUND       35  GROUND       36  --------
                                 37  --------
                                "F" fitting for RF cable connection.
                                Special cables, detailed in the CAR drawing
                                package, connect the CAR PCB and front panel
                                to the modem.
        User adjustments:       RR threshold from -15 to 0 dBmV.
        Out of band sensitivity:At least 50 dB down from ideal carrier
               level.



        MODEMS                                                       Page 22-3

        Pulse width distortion: Less than 10% at 2 Mbaud.
        Data sensitivity:       Modem set must idle at Mark
                                for proper AGC setting in Rcvr.  During
                                data transmission, a mark must appear
                                at least 8% of the time, for 2 Mbaud
                                data.
        Latency:                RF carrier on to CD = 200 msec.

        22.2  DRAWING PACKAGE NUMBERS

        120-029 - Transmitter 120-030 - Receiver

        22.3  RESPONSIBLE ENGINEER

        W.  Struven