We present a wireless recording system designed for high-resolution mapping of gastric slow-wave signals. The system is composed of an implantable unit (IU), a wearable unit (WU), and a stationary unit (SU) connected to a computer. Two independent wireless data communication links consisting of IU-WU and IU-SU were developed based on near-field and far-field communication, respectively. Furthermore, the WU is capable to wirelessly recharge the IU's battery through an inductive link. For the IU-WU near-field communication, a differential pulse position data encoding algorithm with only 6.25% duty cycle, with load shift keying (LSK) modulation is developed to guarantee continuous power transmission and high data transfer rate, simultaneously. The IU sends the encoded data to the WU, and the WU can either store the data locally on a memory card or transmit them to the SU for real-time monitoring. In addition, the IU-SU far-field data communication was developed based on a RF transceiver in which the IU transmits the data directly to the SU. The benchtop validation of the system demonstrated successful IU-WU and WU-SU data transmission, while sample signals were recorded successfully at IU through saline solution and received by SU.