(ט) סדר תקיעות, שלש של שלש שלש. שעור תקיעה כשלש תרועות. שעור תרועה כשלש יבבות . תקע בראשונה ומשך בשניה כשתים - אין בידו אלא אחת. מי שברך ואחר כך נתמנה לו שופר, תוקע ומריע ותוקע שלש פעמים. כשם ששליח צבור חיב, כך כל יחיד ויחיד חיב. רבן גמליאל אומר: שליח צבור מוציא את הרבים ידי חובתן.
(9) The order of sounding the shofar is [that] three [sets] of three blows [are sounded] thrice; the required amount [of time] of the tekiah [long uninterrupted blow], is like [that of] three teruot [interrupted blows], and that of each tekiah is like [that of] three short blows [understood to be like sighs or cries]. If one blew the first tekiah, and prolonged the second, [so as to be] like two, he only has one [tekiah credited to him]. He who has blessed [all the blessings] of the musaf prayer, and [only] afterwards [obtained] a shofar, must blow [the sequence of] tekiah, teruah, and tekiah three times. Just like the [prayer leader] is obligated [to recite the prayers of the day for himself], so is every individual obligated [to do so]. Rabban Gamliel says, "The [prayer leader] releases the public from their obligation [by reciting the prayers out loud for them]."
Talmud Rosh Hashanah 33b
Mishna: THE LENGTH OF THE TERU'AH IS EQUAL TO THE LENGTH OF THREE YEBABOTH (יבבות). (RH 4:9)
Gemara: It is written in the Tanakh that Rosh Hashana shall be for you “a day of teru'ah” (Numbers 29:1). We translate this expression into Aramaic as, “a day of yebaba (יבבא)”. In the Tanakh it is also written of the mother of Sisera, “Through the window she looked forth, (va-teyabab, וַתְּיַבֵּב) and cried out” (Judges 5:28). One authority thought that this means drawing a long sigh, and the other that it means uttering short piercing cries.