Abstract: This abstract describes a system for the field recording of seismic data in which a plurality of geophone outputs are connected to an array terminal. Each geophone is connected to a fixed gain differential amplifier of high gain. The outputs of the amplifiers are square wave and each output goes to one of the parallel inputs of a parallel to serial convertor, through gate means. On a first command from an array controller in a distant recording truck, the gate means are momentarily opened, to store a single bit in each channel corresponding to the sign of the square wave, in the convertor inside the array terminal. The convertor then reads out as a train of serial bits, the stored pulses. This train of single bit signals is carried to the array controller through each of the other array terminals by a single pair of conductors, and stored on a magnetic recording means.

Abstract: This abstract describes a system for the field recording of seismic data in which a plurality of geophone outputs are connected to an array terminal. Each geophone is connected to a fixed gain differential amplifier. A shifting function is produced which is added to the amplified geophone signal to form a sum signal which goes to an axis crossing coder, (AXC). On a first command from an array controller in a distant recording unit, the AXC is commanded to produce axis-crossing-coded pulses of the instantaneous sum signals. These pulses are stored in a parallel-to-serial converter inside the array terminal. On a second command from the array controller the converter reads out as a train of serial bits, the pulses stored in the converter. This train of single bit signals is transmitted to the array controller by a single pair of conductors, and stored on a magnetic recording means.