Pink Noise Generation from White Noise using Current Mode Analog Building Blocks

Pink noise, which has a power spectral density that is inversely proportional to the frequency, is widely used for acoustic applications such as for testing audio equipment. Its generation from white noise requires such a system transfer function that it is not directly realizable in the analog domain, and it is necessary to use an approximation for the frequency of interest. In this study, it is generated from white noise using a fourth-order filter transfer function. The presented circuit is different from the conventional voltage mode pink noise generators in the literature. It uses operational transconductance amplifiers (OTAs) as active building blocks  for the implementation and operates in the current mode. Using  transconductances for filter matching conditions enables to design circuits that do not require large capacitance and resistance values, and this is generally the preferred case when integrated circuit applications are considered.  The active realization in this paper is verified via SPICE simulations. The simulations agree well with the theory, and it can be claimed that adopting current mode approach to analog pink noise generators, especially when integrated circuit applications are regarded, The OTA circuit is a feasible alternative to conventional ones employing operational amplifiers.