Quoting from a book called ‘Principal Upanishads” - by Dr.Anantha Rangachary which based on the sanskrit commentary of Sri Rangaramanuja muni (16th century)
The author refers to Anandavalli section (Anandamaya Vidya) of Taittiriya upanishad and provides the following meaning for "Anantham", for the aphorism
"Satyam Jnanam anatham brahma"
The author says "the Anadavalli which expounds the nature of supreme reality, the goal and the way is introduced with the words
“the knower of the brahman attains the highest" (Brahmavidhapnoti param).
Bramhavid means one who meditates upon Brahman which is infinitely great by its nature and also on account of its qualities.
Meaning of Anantham:
The word “Anantham” signifies that it is not limited spacially, temporally or with reference to a substance.
This is here, not elsewhere is the form of “desaparicheda”
It is now, not at any other time is the form of “Kalaparicheda”
This is not this” is “Vastuparicheda”.
So, Brahman has “sarvavastu samanadhikaranyarhatva” and so is without any limitations related to the substance.
This non-limited nature in respect of substance also means infinite excellence of qualities on account of which it is without an equal or a superior.
The meaning of the word “Anantham” also means the infinite nature of its auspicious qualities.
So, the Vedas claim too-that he knows the Lord’s greatness to be unknowable. This is borne out by the Anandavalli vAkya
“YatO vAchO nivartantE, aprApya manasA saha”
Veda Vakyas, which set out to describe fully at least one attribute of the Parama Purusha , return vanquished, unable to fathom the full depth of each auspicious quality.
As per Ramanujacharya, Brahman is defined as anantham or infinite because it is omniscient, it exists at all time and it pervades all other objects in the universe. This charaterestic of Brahman distinguishes it from the nitya jivas or the eternally free souls because the later are monadic in character (Anu), whereas brahman is Vibhu or all pervasive.
For Madhvacharya, the term anantam or infinity means that which is not conditioned by space, time and gunas (desakalaguna aparichinnatvam).
So, as per the Ramanujacharya and Madhvacharya, BRAHMAN is Qualified by Satyatva, Jnanatva and Anatatva.
As per Shankaracharya, the three terms convey the bramasvarupa, i.e. Brahman doesn't possess these characteristics, but it is itself reality, pure knowledge and infinite.
So, as per Ramanujacharya and Madhvacharya, in a nutshell, the only way of comprehending the ParamAtmA’s grandeur is to realize that it is beyond comprehension, being infinite on characharacter.
For more details refer to Philosophy of Upanishads by Dr.S.M.Srinivasachari