Interface Kit for EV9900A

EV9902

Figure 9 – The BER Measurement Tab

A 511-bit pseudo random bit sequence (PRBS) generated at the transmitting and receiving ends

is used to calculate the bit error rate. Each byte received is compared with the corresponding byte

in the locally generated PRBS and from this the number of bits/blocks received in error is

calculated.

It is assumed that prior to beginning a bit error rate measurement that the various CMX990

registers have been written with the values for the required modem and RF settings. This can be

done with the individual tabs or with a script using the Script Handler tab. The various controls on

the BER Measurement tab are described below.

Transmit radio button – Select transmit mode.

Receive radio button – Select receive mode.

Unit measurement radio button – Transmit or receive a specified number of bits/blocks.

Continuous measurement radio button – Transmit or receive bits/blocks until Stop button is

pressed.

Bit sync. edit box – Specify 2 byte bit sync. pattern. Default pattern is 0xCCCC.

Frm. sync. edit box – Specify 2 byte frame sync. pattern. Default pattern is 0x4567.

Ctrl. data edit box – Specify 2 byte control data pattern. Default pattern is 0xA63F.

Raw data radio button – Select transmit or receive in raw data mode. Raw data mode is 2 bytes

of bit sync., 2 bytes of frame sync. followed by a repeating 511-bit pseudo random bit sequence

transmitted a byte at a time.

Mobitex radio button – Select transmit or receive in Mobitex mode. Mobitex mode is 2 bytes of

bit sync., 2 bytes of frame sync., 2 bytes of control data, 1 byte of FEC for the preceding 6 bytes,

followed by a repeating 511-bit pseudo random bit sequence transmitted in blocks of 18 bytes.

Bit count drop down box – Select the number of bits to transmit or receive. Selectable values

are 10000, 100000 and 1000000 bits. Default selection is 100000 bits. The selected value only

applies when unit measurement and raw data mode are selected.

©

CML Microsystems Plc

17

2009

UM9902/3