Method and apparatus for counting transmission errors in a digital microwave link

Claim 1

A method of counting transmission errors in a digital microwave link for producing a demand of commutation onto an emergency channel when the quality of the link becomes deficient, wherein the errors are counted during a period t which is always at least equal to a value t 1 and at most equal to a value t 2 , and which period terminates when a fixed number N of errors has been detected, a pulse is stored upon each detection of N errors within a period t, and a demand of commutation is produced when n 1 pulses have been stored consecutively.

Claim 2

A method of counting transmission errors in a digital microwave link for producing a demand of commutation onto an emergency channel when the quality of the link becomes deficient, wherein the errors are counted during a period t which is always at least equal to a value t 1 and at most equal to a value t 2 , and which period terminates when a fixed number N of errors has been detected, a pulse is stored upon each detection of N errors within a period t, and a demand of commutation is produced when n 1 pulses have been stored consecutively.

Claim 4

An apparatus for counting transmission errors in a digital microwave link, and for producing a demand of commutation onto an emergency channel when the quality of the link becomes deficient, comprising an error counter producing an error signal SA after detection of N errors, a time base operable to deliver pulses T 2 with a period of t 2 and signals T 1 of duration t 1 <t 2 triggered by said pulses, a register connected to the counter and having an enable input, means for generating a commutation demand when said register has stored n 1 consecutive error signals, and a logic circuit comprising first flip-flop means connected to said error counter and clocked by said signals T 1 and having its output connected to said error counter and said time base for resetting thereof, second flip-flop means having its clock input connected to the error counter, a first output Q connected to the enable input of the register while a second inverted output Q is connected to the time base and the error counter for resetting thereof, and third flip-flop means clocked by said pulses T 2 and connected to said error counter and having its output connected to the enable input of the register.

Claim 5

An apparatus for counting transmission errors in a digital microwave link, and for producing a demand of commutation onto an emergency channel when the quality of the link becomes deficient, comprising an error counter producing an error signal SA after detection of N errors, a time base operable to deliver pulses T 2 with a period of t 2 and signals T 1 of duration t 1 <t 2 triggered by said pulses, a register connected to the counter and having an enable input, means for generating a commutation demand when said register has stored n 1 consecutive error signals, and a logic circuit comprising first flip-flop means connected to said error counter and clocked by said signals T 1 and having its output connected to said error counter and said time base for resetting thereof, second flip-flop means having its clock input connected to the error counter, a first output Q connected to the enable input of the register while a second inverted output Q is connected to the time base and the error counter for resetting thereof, and third flip-flop means clocked by said pulses T 2 and connected to said error counter and having its output connected to the enable input of the register.