# A Reconfigurable Radio-Frequency Converter IC in 0.18 \(\upmu\)m CMOS
## 1 Introduction  
The demand for services in current communications networks has experienced a heavy growth in recent years, and it is predictable that this trend will continue in the future, or even rise, because consumers demand access to an increasing amount of information using more and more different devices [1]. From the standpoint of service providers, this poses a severe challenge in terms of research and innovation in the design and implementation of communications systems.  
DVB-T tuners have been reported for some years, with realizations in the early 1990s [2], and have since remained a popular field of research [3; 4; 5; 6; 7; 8]. They have a wide spread both in the technology in which they are implemented, which ranges from standard Si CMOS technologies of down to 40 nm [7] to other technologies such as SiGe BiCMOS [6]. Also, they are typically intended for direct RF antenna inputs in the available bands (UHF, VHF, L-band...).  
One field of active research in the communications industry is broadband global networks, which today allow providers to offer jointly high-speed access to the Internet, telephone lines and television broadcasting using a single network to the end user. The concept of combining these three services is referred to as _triple-play_. The first attempt to deploy triple-play commercially was carried out in Italy back in 2001 by the operator Fastweb, using a fiber-to-the-home (FTTH) infrastructure [9]. This strategy was proven right and allowed them to lead in the average revenue per user (ARPU) rankings for some consecutive years [10], which has fueled most telecommunications operators to follow this approach. Presently, FTTH networks are being deployed to offer triple-play solutions around the world.  
To provide triple-play, operators must have a network capable of carrying all three services simultaneously. Of them, the most demanding one in terms of bandwidth is television broadcasting, which today typically requires 10 Mbit/s to 15 Mbit/s alone [11]. With today's technology, network infrastructures suitable for triple-play services can be deployed based on copper, cable or optical fiber, although the latter shows a clear advantage in terms of bandwidth [12]. Besides  this, networks based on optical fiber also introduce lower attenuation, which allows covering larger distances between provider and clients; they permit the implementation of point-to-multipoint (P2 MP) tree structures; and, consisting of passive elements, they are very cost-efficient and easy to maintain. For this reason, networks based on passive optical fiber with gigabit capabilities (GPON) are the preferred choice to implement FTTH for triple-play solutions [1].  
In a conventional triple-play implementation, both telephone lines and television broadcasts tend to be IP services (VoIP and IPTV, respectively) that along with Internet access, share the whole bandwidth of the subscriber. Typically, telephone lines and Internet provision share a common background among service providers, but the broadcast of television contents in triple-play brings with it a series of issues that need to be addressed separately. Among them, the most critical one is the saturation of the clients' available bandwidth, which is even more pressing with the demand of contents featuring ultra-high definition (UHD) at 4K or even 8K.  
In this respect, practical implementations to deliver 4K and 8K contents require, respectively, over 20 Mbit/s and 40 Mbit/s of bandwidth, if virtual reality (VR) content needs to be streamed, even  with compression [13]. This bandwidth needs to be taken from the clients' overall bandwidth, thus limiting the capabilities for other services, which in turn require an increasing bandwidth to allow the simultaneous use of several different devices at home. This issue is even more critical if we take into account that in a typical household, several television sets might be used at the same time to watch different channels, each of them requiring its own bandwidth.