A stimulator and a method for the treatment of intractable pain syndromes by electrical stimulation of the spinal cord is disclosed. An example method includes positioning a first pair of implantable electrodes to a dura matter in an epidural space proximate to a subject's spinal cord at predetermined locations, positioning a second pair of implantable electrodes to the dura matter in the epidural space proximate to the subject's spinal cord at predetermined locations, and transmitting signals of first and second frequencies through the first and second pairs of implantable electrodes respectively, so that the signals of the first and second frequencies interfere with each other to produce at least one beat signal proximate to the subject's spinal cord. The at least one beat signal has a frequency within a range of more than 250 Hz to about 15,000 Hz.
