CSM TESTING APPARATUS IN BACKWARD CDMA CHANNEL AND TEST DATA GENERATING METHOD

摘要

PURPOSE: A CSM(Cell Site Modem) testing apparatus in a backward CDMA channel and a test data generating method are provided to increase a reliability and a stability of a channel card by generating a test data to use it as an input data of a test circuit, constructing a white Gaussian noise generating circuit and obtaining a signal-to-noise ratio with an output signal of the White Gaussian noise generating circuit and the test data. CONSTITUTION: A pattern and a speed of a data to be tested are determined, and in this respect, a data of a speed of 1200bps is preferably selected to reduce a burden to a RAM(S1). A quality indicator is added to the data to be tested having a data speed of 9600bps and a 4800bps(S2). The reason for adding the quality indicator only to the 9600bps and 4800bps data is to slow the speed of substantial information data as the amount of the actual data becomes small. A tale bit of 8 bit of every 0 is added to the data(S3). The data is convolution-coded to correct an error generated due to a noise and an interference in a radio interval of the data(S4). A code symbol repetition is performed with the data, one of which is actually transmitted(S5). The data is read to perform a block interleaving. This is to make random a burst error, and the data is recorded in the block interleaver in a line unit and read in a column unit(S6). One of 64 modulated symbols is corresponded to every 6 code symbol for the data(S7). It is determined each data is to be transmitted by using the data transfer rate of a frame and a part of the code for the data(S8). A long code is generated for the data determined to be transmitted(S9). The long code is orthogonally spread to complete a test data(S10).