The TETRA network can be considered as two parts, the handset and the infrastructure. The infrastructure is entirely digital (assumes digital connection to the PSTN) whilst the terminal contains both analogue and digital components.
Basic reference configuration for a TETRA system
Figure above shows a basic reference configuration for the TETRA system. Only the voice transmission aspects are shown and the following functions are included.
The linear PCM points within the terminal and infrastructure are important as they provide a point at which the performance of the system can be measured without involving the TETRA CODEC or radio link (although final testing should be performed from end to end). When testing at the linear point within the terminal the 16 bit linear PCM signal shall be inserted and extracted to an external calibrated reference PCM CODEC allowing measurements to be easily made.
The ear and mouth reference points are as defined in [P.64].
Copyright ©2002 Andy Fletcher andy@x31.com