From what you describe I assume you purchased Treasury Notes at a discount which will pay you coupon interest (possibly adjusted for accrued interest paid at acquisition), which all gets reported on 1099-INT.
Separately, the 'discount' on those notes results in 'accrued market discount' at disposition not a gain/loss, which like all bonds is reportable as interest on Schedule B but will not have a 1099-INT.
The combination of these two is what gives you the total yield on the Notes (e.g. 10k par of 2.5% Notes purchased at price of 98 maturing in 12 months will yield $250 in 1099-INT income and $200 in AMD)
In your 1099-B from the broker you should have a list of sales/redemptions for these Notes which will have these amounts reported in Box 1f? That should part of the section reported to the IRS (short/long term covered sales etc) not in some memo pages at the back tho. These AMD amounts should correspond to the discount you purchased the bonds at, and after the AMD adjustment you should zero gain/loss in your 1099-B on these.
