BAND LIMIT CIRCUIT, COMMUNICATION DEVICE, COMMUNICATION NETWORK SYSTEM, AND BAND LIMITING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a band limit circuit and band limiting method, capable of limiting a band at a PHY layer level in a communication network system as well as a communication device and communication network system capable of limiting a band for every communication line, by solving the problem of a band being difficult to be limited for each communication line which is provided to a user, because it is not possible to determine whether a plurality of packets have been transmitted on the same communication line.;SOLUTION: A cycle counter 3 counts the number of clocks CLKA generated by frequency-dividing a transmission clock CLK. A comparator circuit 7 outputs a clear signal B1, when the count value exceeds the holding value of a cycle register 5. A limit counter 4 counts the number of clock CLKB of AND of an effective frame signal A1 and the clock CLKA. An over limit detecting circuit 8 outputs a limit exceedance detecting signal B3, when the count value B2 exceeds the holding value of a limit register 6. An effective frame signal control circuit 9 controls, when the over limit detecting signal B3 is inputted, so that the effective frame signal A1 is invalidated and outputs an effective frame signal A3.;COPYRIGHT: (C)2002,JPO