As shown below by the purple line, real GDP peaked in Q1 1980 and then declined thru Q3 1980 during Volcker's mini-recession.

During that two-quarter interval of "shallow and short," real GDP contracted by just 2.2%. But the inflation rate (brown line) just kept climbing, rising at an annualized rate of 9.5% during the period.

The second round of the Volcker anti-inflation medicine took another chunk out of real output — this time 2.6% from the Q3 1981 peak to the Q4 1982 bottom. Still, inflation stubbornly resisted the recessionary medicine, rising at a 5.3% annual rate during the five-quarter downturn.