NBC logged a narrow primetime demo victory in the final week of the summer season, staying on top in the first frame following its coverage of the Summer Olympics.

The return of “America’s Got Talent” and “Deal or No Deal” put the net over the top, and it also saw solid numbers for the debut of “America’s Toughest Jobs.”

Week was also highlighted by coverage of the Democratic National Convention in Denver. The broadcast nets devoted the 10 o’clock hour to the event Monday through Thursday, but they were topped in the ratings by CNN on the final night.

Overall for the Aug. 24-31 sesh, Nielsen estimates that NBC finished on top with a 1.7 rating/5 share in adults 18-49, followed closely by Fox and Univision (1.6/5). CBS (1.4/4) and ABC (1.3/4) were in a battle for fourth, with ESPN claiming fifth (1.0/3).

The Peacock also prevailed in both adults 25-54 (2.1/6) and total viewers (5.9 million).

It was the fourth straight week that NBC finished on top in 18-49, and it marked the first time in 2008 that Fox had not finished on top during a week with no major sporting events. (NBC had won the first week of the year with the NFL playoffs and then three straight in August with the Olympics, while ABC took one week in June thanks to the NBA Finals.)

For NBC, “America’s Got Talent” returned atop the rankings in both 18-49 (3.1/9) and total viewers (11.12 million). The Peacock also claimed three other shows in the top five: the combo of “Deal or No Deal” (2.8/9, 11.00m) and “America’s Toughest Jobs” (2.7/7, 7.30m) on Monday and a second “Talent” on Wednesday (2.8/8, 10.34m).

In a rarity, the net was hampered by preseason NFL action (a lowly 0.8/3 in 18-49, 2.80m for Thursday’s Washington-Jacksonville matchup), but it was the top-rated broadcaster for the Dems’ convention.

Fox was paced by a repeat “House” (2.3/6 in 18-49, 6.81m), the return of “Moment of Truth” on Thursday (2.1/6, 5.18m) and potent numbers for Saturday’s “America’s Most Wanted” (1.8/6, 5.02m).

At CBS, “Big Brother” won two of its three hours in demos — led by Tuesday’s seg (2.3/6 in 18-49, 6.28m) — but “Swingtown” hit a low as it winds down (1.1/4 in 18-49, 3.65m).

ABC saw “Wipeout” slip to a firstrun low (2.3/7 in 18-49, 6.32m), though it ranked seventh for the frame, but the net was lifted by the season opener of “Saturday Night Football” (1.9/7 in 18-49, 5.60m).

As for the Democratic National Convention, Nielsen estimates that Thursday’s 10 o’clock hour — highlighted by Barack Obama’s speech in which he accepted the party’s presidential nomination — averaged a whopping 38.38 million viewers on broadcast and cable networks and an estimated 3.5 million on PBS as well.

Coverage averaged a 21.0 household rating among African-Americans, compared with a 12.5 for Hispanics and 12.4 for whites.

In cable, CNN’s coverage of Thursday’s 10 o’clock hour ranked sixth among all primetime programs for the week in 18-49 (2.5/7). And in total viewers, its 8.06 million ranked fifth and helped lift the news net to a first-place cable finish in total viewers (3.15 million on average for the week).

ESPN was the top cabler among 18-49ers on the strength of Sunday’s “NASCAR Sprint Cup” (2.1/8 in 18-49, 5.64m) and a preseason “Monday Night Football” game (1.5/4, 4.01m) for Seattle-San Diego on Monday).

Among entertainment programs, MTV’s “The Hills” (2.2/6 in 18-49, 3.43m) was the top cable skein and stood No. 11 in 18-49 among all shows.

ABC Family’s “Secret Life of the American Teenager” remained hot (1.3/4 in 18-49, 3.65m), serving as a strong lead-in for “Greek,” which hit series highs for its season preem (0.6/2 in 18-49, 1.55m).

Oxygen’s “Janice Dickinson Modeling Agency” kicked off its fourth season Tuesday with the show’s largest aud to date among 18-49 (322,000). And Wednesday, Bravo’s “Shear Genius” hit highs with its finale (1.3/4 in 18-49, 2.54m), airing behind “Project Runway” (1.8/5, 3.55m).