Time compression multiplex digital transmission system

Claim 2

A digital transmission system, comprising: means 50, 51, 52, 53, 54, 23) for transmitting bursts of digital signals of fixed length (B) at fixed frame intervals (F), each burst including initial and final synchronization bits (0 and 81 or 82 and 163) at the beginning and ending respectively of each burst; and means (11, 12, 20) for receiving the bursts of digital signals, including means for establishing frame synchronization: characterized by, in the receiving means: gating means (12, 13, 17, 28) responsive to the absence of frame synchronization (Q 2 =0) for passing all received signals to the frame synchronization establishing means (30); and responsive to the presence of frame synchronization (Q 2 =1) for passing only signals received during a window period which is coextensive with that of said bursts, to the frame synchronization means.

Claim 3

A digital transmission system having a central station and a remote station each including transmitting and receiving means as defined in claim 1 for alternately transmitting and receiving bursts of digital signals over a single transmission path; characterized by, the central station transmitting means including means (65, 66, 67) for initiating transmission of each burst at a fixed frame interval; and the remote station transmitting means including means (21) for initiating transmission of each burst immediately after the remote station receives the burst from the central station transmitting means; whereby the frame interval is not less than the total period of the two bursts from the central and remote transmitting means plus twice the transmission delay over the single transmission path.

Claim 4

A digital transmission system as defined by claim 2 in which the remote station is additionally characterized by means (50, 53) for enabling the transmitting means only when the signal confirming frame synchronization (Q2=I) is present.

Claim 5

In a digital transmission system, comprising: means (50, 51, 52, 53, 54, 23) for transmitting bursts of digital signals of fixed length (B) at fixed frame intervals (F), each burst including initial and final synchronization bits (0 and 81 or 82 and 163) at the beginning and ending respectively of each burst; and means (11, 12, 20) for receiving the bursts of digital signals, including clock recovery means (14) for generating clock pulses synchronized to bits of the digital signals received from the transmitting means: the improvement characterized by, in the receiving means: first means (30) responsive to the initial and final synchronization bits for generating a signal confirming frame synchronization (Q 2 = 1); second means (21, 22, 26) responsive to the clock pulses and the initial synchronization bit for generating a gating signal having a period coextensive with that of said bursts; and gating means (12, 13, 25, 27, 28) responsive to the absence of the signal confirming frame synchronization (Q2=0) for applying the received signal bursts to said first (30) and second generating means (21, 22, 26) and responsive to the presence of the signal confirming frame synchronization (Q 2 =1) for applying the received signal bursts to said first and second generating means only during the presence of the gating signal.

Claim 6

In a digital transmission system, comprising: means (50, 51, 52, 53, 54, 23) for transmitting bursts of digital signals of fixed length (B) at fixed frame intervals (F), each burst including initial and final synchronization bits (0 and 81 or 82 and 163) at the beginning and ending respectively of each burst; and means (11, 12, 20) for receiving the bursts of digital signals, including clock recovery means (14) for generating clock pulses synchronized to bits of the digital signals received from the transmitting means: the improvement characterized by, in the receiving means: first means (30) responsive to the initial and final synchronization bits for generating a signal confirming frame synchronization (Q 2 = 1); second means (21, 22, 26) responsive to the clock pulses and the initial synchronization bit for generating a gating signal having a period coextensive with that of said bursts; and gating means (12, 13, 25, 27, 28) responsive to the absence of the signal confirming frame synchronization (Q2=0) for applying the received signal bursts to said first (30) and second generating means (21, 22, 26) and responsive to the presence of the signal confirming frame synchronization (Q 2 =1) for applying the received signal bursts to said first and second generating means only during the presence of the gating signal.