The industrial sector of cheese production with specific quality protection occupies a relevant position in the industrial context of the European Union. In order for the sector to improve the competitiveness, solutions with emphasis in technological innovations should be done which increases the automation and quality control in the productive process. Moreover, the laws regulating the food industry in Europe establish that "the food traceability in all the production, transformation and distribution stages has to be guaranteed". Nowadays, the sector has no a procedure that exhaustively guarantees a proper traceability throughout the cheese ripening due to the fact that the surrounded conditions such as humidity, temperature, product handling (turning) and mold growing avoid the individual labeling of the products. Is for this that the production and quality control are performed by batches and the data storage is doing manually by the company personnel. This paper deals with the possibility of carrying out an individual and by batches quality control of the product in cheese industries. By means of RFID tags a complete traceability is performed improving the cheese fabrication process monitoring and production control.

For practical applications, the fractional-order integral and differential operators require to be approximated as stable, causal, minimum-phase integer-order systems, which usually leads, in both continuous and discrete domains, to high order transfer functions. Assuming that an approximation of good quality is available for the fractional operator, efficient implementations, in both cost and speed, are required. The fast development of the microelectronics gives us the opportunity of using cheap, accurate, programmable, and fast devices for implementing reconfigurable analog and digital circuits. Among these devices, field programmable gate arrays, switched capacitor circuits, and field programmable analog arrays are used in this paper for the implementation of a fractional-order integrator, previously approximated by recursive Oustaloup’s method. The fundamentals of the devices as well as the design procedures are given, and the implementations are compared considering their simulated frequency responses, the design efforts, and other important issues.

The implementation of a fully-differential (FD) instrumentation amplifier (IA), based on indirect current feedback (ICF) and aimed to electrical impedance measurements in an Internet of Things (IoT) biomedical scenario, is presented. The IA consists of two FD transconductors, to process the input signal and feed back the output signal, a summing stage, used to add both contributions and generate the correcting current feedback signal, and a common-mode feedback network, which controls the DC level at the output nodes of the circuit. The transconductors are formed by a voltage-to-current conversion resistor and two voltage buffers, which are based on a super source follower cell in order to improve the overall response of the circuit. As a result, a compact single-stage structure, suitable for achieving a high bandwidth and a low power consumption, is obtained. The FD ICF IA has been designed and fabricated in 180 nm CMOS technology to operate with a 1.8-V supply and provide a nominal gain of 4 V/V. Experimental results show a voltage gain of 3.78 ± 0.06 V/V, a BW of 5.83 MHz, a CMRR at DC around 70 dB, a DC current consumption of 266.4 $\mathsf{\mu }$A and a silicon area occupation of 0.0304 mm${}^2$.

The design of an instrumentation amplifier (IA), based on indirect current feedback and suited to electrical bioimpedance spectroscopy, is presented. The IA consists of two transconductors and a summing stage, featuring a single-stage configuration process that allows the maximum achievable bandwidth to be extended. The transconductors are linearized by means of resistive source degeneration, whereas the use of super source followers allows a reduction in the values of the source degeneration resistors. This fact leads to a decrease in the overall noise and the silicon area, thus resulting in a compact implementation. A thorough analysis of the proposed solution, accompanied by a design procedure and verified by means of electrical simulations, is also provided. Two versions of the IA, i.e., a single-ended (SE) and a pseudo-differential (PD) structure, were designed and fabricated using 180 nm CMOS technology to operate with a 1.8 V supply. The experimental results, including a BW of 5.2 MHz/8.0 MHz, a CMRR higher than 72 dB/80 dB, a DC current consumption of 139.0 $\mathsf{\mu }$A/219.3 $\mathsf{\mu }$A and a silicon area equal to 0.0173 mm${}^2$/0.0291 mm${}^2$ for the SE/PD implementation, validate the suitability of the approach.

A CMOS widely tunable second-order $G_m$-C bandpass filter (BPF), intended to be used in multi-sine bioimpedance applications, is presented. The filter incorporates a tunable transconductor in which the responses of two linearized voltage-to-current converters are subtracted. As a result, the effective transconductance can be continuously adjusted over nearly three decades, which allows a corresponding programmability of the center frequency of the BPF. The circuit was designed and fabricated in 180 nm CMOS technology to operate with a 1.8 V supply, and the experimental characterization was carried out over eight samples of the silicon prototype. The simulated transconductance of the cell can be tuned from 5.3 nA/V up to 19.60 $\mathsf{\mu }$A/V. The measured range of the experimental transconductance varied, however, between 1.42 $\mathsf{\mu }$A/V and 20.57 $\mathsf{\mu }$A/V. Similarly, the center frequency of the BPF, which in the simulations ranged from 500 Hz to 342 kHz, can be programmed in the silicon prototypes from 22.4 kHz to 290 kHz. Monte Carlo and corner simulations were carried out to ascertain the origin of this deviation. Besides, the extensive simulation and experimental characterization of the standalone transconductor and the complete BPF are provided.

A bandpass filter (BPF), with high quality factor ( Q ) and wide tuning range of the centre frequency ( $f_0$ ), for signal separation in simultaneous multi-sine bioimpedance analysis, is presented. The cell follows the $G_m$ - C approach, where a multiple-output transconductor has been incorporated, for the sake of compactness, and a fully-differential structure has been selected, to enhance the general performance of the solution. The linearized transconductors ( $G_m$ ) are based on a double asymmetric differential pair and the integrated capacitors ( C ) are implemented in such a way that the required transfer function for the differential-mode signal is achieved and the stability of the common-mode component is granted. The BPF has been designed and fabricated in 180 nm CMOS technology to operate with a 1.8-V supply and feature a nominal gain at $f_0$ of 0 dB and a Q equal to 20, whereas $f_0$ is programmed by modifying the biasing current of the transconductors. Experimental results, measured on 8 samples of the silicon prototype, show that the BPF centre frequency can be continuously swept from 102 Hz to 2.06 MHz with a supply current ranging between 981 nA and 686 $\mu$ A. Besides, the maximum output voltage range of the filter, determined according to the –40 dB THD criterion, varies between around 31.5 mV and 64 mV within the frequency range indicated, thus leading to a dynamic range between 42.3 dB and 48.6 dB, which illustrates its suitability for the target application.