GATED CLOCK/DATA MUX (GC/DM) CARD - TM-11-5805-688-14-10129

T.O. 31W-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3011

(DRIO), are routed to the GC/DM card. Each 4-bit

5-118. The system clock distribution circuits generate

channel address applied to the GC/DM card causes one

system clock signals DRIO from system clock signal RI

gated clock signal to be generated to the channel card

from the FS card. Signals DRIO are routed as timing

identified in the channel address. The end-of-scan

signals to the seq and GC/DM cards. The end-of-scan

generation circuits generate complementary end-of-scan

7eneration circuits produce end-of-scan signal

signals DEOS and DEOS- that are applied to the OEG

DEOS3NX when word 29 signal DW29 from the GC/DM

and ERD cards. The signals are generated when the

card and end-of-scan signal DEOS from the seq card

port count in the sequencer timing circuits is equal to

are applied. Signal DEOS3NX is routed as a timing

the maximum number of used ports selected by the five

signal to the CRC circuit on the SB card(s).

PORTS IN USE switches. Complementary end-of-scan

signals DEOS2 and DEOS2- are derived from signal

5-119. GATED CLOCK/DATA MUX (GC/DM) CARD.

DEOS and the signals are applied to the FS card. In

turn, complementary end-of-scan signals DEOS2B and

5-120. The GC/DM card generates the gated clock

DEOS2B- are also derived from signal DEOS. These

signals that are applied to the channel cards in the

two signals are routed to the OEG, GC/DM, and ERD

demultiplexer. The card also generates the three stuff

cards. The overhead port sequence selector circuit

command codes and timing signals that are applied to

produces minor frame equals port sequence signal

the common cards in the demultiplexer as described in

DMF=PS during each minor frame period that is eligible

the following paragraphs. The gated clock generation

to provide overhead service to an assigned used port.

circuits produce gated clock signals (DGCO1 through

The signal is applied as an enable signal to the GC/DM

DGC15) as required to service the active channel cards.

card during word 29 to allow a positive or negative stuff

Each active channel card has a designated gated clock

to be performed. The five minor frame count signals,

signal. For example, channel card No. 1 receives signal

DMFCO through DMFC4, that are applied to the circuit

GCO1 each time a gated clock is designated to the

from the ERD card contain the minor frame number of a

channel card. Positive stuff enable signal DPSE applied

given minor frame being received in the demultiplexer at

to the circuits during word 29 causes one additional

any given time.

gated clock signal to be generated to a selected channel

card as part of the overhead service function. In turn,

5-116. OVERHEAD ENABLE GENERATOR (OEG)

negative stuff enable signal DNSE results in deletion of

one gated clock signal during word 29 to the selected

CARD.

channel card. Minor frame equals port sequence signal

DMF=PS applied to the circuits is an enable signal that

5-117. The OEG card generates timing signals that are

allows a positive or negative overhead service to be

used in the demultiplexer function.

The word 24

performed during word 29 of a given minor frame

generation circuits generate word 24 signal DW24NX

period. Signal DMF=PS is not generated during minor

when the word count in word count signals DWCO

frame periods that are not eligible to provide overhead

through DWC4 from the GC/DM card is count 23, and

servicing.

end-of-scan signal EOS is applied from the end-of-scan

generation circuits. Signal DW24NX is routed to the

CRC circuits on the SB card(s) as a timing signal.

5-28