Complex signal generation and transmission

DETAILED DESCRIPTION These and other objects of the present invention are achieved by an apparatus which stores in a first digital memory a plurality of amplitude samples of single frequency and multi-frequency signalling, status and test signals.
The complete set of required samples may be retrieved from the memory as needed without the need for a plurality of time base signal generating means.
Additionally, the signal to noise ratio of the required signals is increased by storing samples in a digital code which defines the n statistically predicted equally likely amplitude ranges of the entire set of signals.
Thus, the more likely amplitudes are defined by more code characters than are the less likely amplitudes.
Additionally, the signal to noise ratio of the entire set of signalling symbols is increased while minimizing digital storage requirements of the system by employing a second digital memory for storing a single amplitude within each of the aforementioned ranges.
The code characters in the first memory are used as index vectors which identify and select a single amplitude in the second memory which is to be retrieved and transmitted.