a variety of other environmental and formation information may be obtained by sensors 40 the signal generated by sensors 40 may typically be analog which must be converted to digital data before electromagnetic transmission in the present system the signal generated by sensors 40 is passed into an electronics package 42 including an analog to digital converter which converts the analog signal to a digital code utilizing 34 ones 34 and 34 zeros 34 for information transmission electronics package 42 may also include electronic devices such as an on off control a modulator a microprocessor memory and amplifiers electronics package 42 is powered by a battery pack which may include a plurality of batteries such as nickel cadmium or lithium batteries which are configured to provide proper operating voltage and current once the electronics package 42 establishes the frequency power and phase output of the information electronics package 42 feeds the information to electromagnetic transmitter 34 electromagnetic transmitter 34 may be a direct connect to drill string 30 or may electrically approximate a large transformer the information is then carried uphole in the form of electromagnetic wave fronts 46 which propagate through the earth these electromagnetic wave fronts 46 are picked up by receiver 48 of electromagnetic repeater.