It was named Plateau de Bure Interferometer (PdBI), and consisted of six antennas operating in the bandwidths 81-115 GHz and 205-245 GHz [14], until it was upgraded and renamed NOEMA (Northern Extended Millimetre Array), currently consisting of the 12-antenna interferometer and equipped with new-generation receivers [15; 16]. Concerning the Italian scenario, the 64 m diameter SRT represents the main telescope with which high-frequency observations are possible in conjunction with the Medicina and Noto 32 m telescopes [17]. The SRT is the result of a scientific and technical project carried out by the Italian National Institute for Astrophysics (INAF) and it is managed by the Astronomical Observatory of Cagliari. Although the telescope was designed to operate in a frequency range between 300 MHz and 116 GHz, at present, its maximum observational frequency is 26.5 GHz. In fact, the SRT is currently equipped with three cryogenic front ends, covering a portion of the P-band (305-410 MHz), L-band (1300-1800 MHz) [18], C-band (5.7-7.7 GHz) [19], and K-band (18-26.5 GHz) [20]. The availability of these radio receivers [21] allowed the SRT to be employed in several scientific and space surveillance observations [22; 23; 24; 25]. One of the main technical features of the telescope is its 64 m primary mirror, which is composed of about a thousand aluminium panels sustained by precision mechanical actuators that are digitally controlled to compensate for the gravitational and systematic deformations of the reflector. This feature is known as active surface and it allows an antenna efficiency of up to approximately 40% to be obtained at high frequencies [26]. Some years ago, with the idea of gaining experience with a radio receiver that operates at high frequencies and testing the performance of the SRT (i.e., telescope active surface and metrology system), the Astronomical Observatory of Cagliari acquired a dismissed W-band receiver developed by IRAM, which was installed on one of the PdBI antennas until 2006. The W-band receiver prototype from IRAM, described in this paper, was adapted and characterised in the INAF laboratory. However, the installation of the prototype in the SRT antenna was not finalised, since in the meantime, the Italian Ministry of University and Research funded the major INAF proposal for the SRT high-frequency upgrade [27], known as the National Operational Program grant (PON), which included the development of a high-performance W-band multi-beam receiver in the Work Package n. 1, as known as PON OR1. The commissioning of the novel instrumentation acquired for the SRT in the framework of the PON grant is underway and the results will be described in separate articles. The receiver acquired from IRAM is a dual-feed system that covers two frequency bands simultaneously: a portion of the W-band (84-116 GHz), also known as the 3 mm band, and a frequency range between 210 and 248 GHz (1.3 mm band) [28; 29]. The instrument observed single linear polarisations and operated at cryogenic temperature to achieve a low receiver noise temperature [28; 29]. All of the components of the receiver could be controlled and managed by a microcontroller using an Ethernet link. Since the SRT was designed to cover all frequencies up to 116 GHz, only the 3 mm channel of the ex-PdBI receiver was upgraded and is presented in this work. The original version of the instrument was unsuitable for the SRT and it required significant modifications and refurbishment from the point of view of its structural and logistical characteristics and its electronic control system [30; 31]. In this paper, a feasibility study of the upgrade of the ex-PdBI receiver for the adaptation to the SRT is presented. One of the goals of the upgrade was to equip the receiver with a new electronic control system based on onboard intelligence that permits smart remote control. In Section 2, we present the original version of the receiver, and focus on its signal acquisition chain of the 3 mm channel.