Independent presidential candidate John B. Anderson brought his give-the-voters-a-choice campaign here today, praising the Orioles baseball team, belittling President Carter and asking for the signatures he needs to get his name on Maryland's November ballot.

Getting the required 55,517 signatures, however, will only be the first step for Anderson. Before he can qualify for the ballot, he must win a court decision invalidating the state law that says he got started too late to be an official candidate in the fall.

Citing the Maryland requirement that one-third of his signature petitions be filed by March 3, -- six weeks before he declared his independent candidacy -- Anderson told a press conference that "any requirement to have signatures that far in advance is an unreasonable restraint."

Earlier, he had told a cheering downtown crowd of about 700 people that "You don't even have to give me your hearts at this early date. I'd like to have them. But for now, give me your signatures."

Anderson campaign workers said today that they have already amassed 25,000 signatures, and hope to collect another 75,000 in the next week, to give their campaign a comfortable margin for error and to pay the way for a court challenge by the end of the month.

In Virginia and the District of Columbia, Anderson's task will be easier. Campaign workers said today they expect little trouble meeting Virginia's requirements and filing the required 10,003 by the September 5 deadline.In the District, 2,500 signatures must be filed by Aug. 19.

Petition drives for Anderson are scheduled to start in both Virginia and the District early in July.

Anderson has already qualified for the ballot in Kansas, New Jersey and Utah, his press secretary Rosalnd Jewett said today. Anderson himself added that he has filed enough signatures to qualify in four other states, although he has not been officially certified in all of them.

To be a viable candidate in his own mind, he added, he should be qualified in approximately 40 states. "I would regard (this)," he said, "as a minimum threshold."

Of all the area jurisdictions, Maryland would seem most fertile for the Anderson candidacy, according to political observers. The states voters have long been noted for taking hold of dark horses, as was most recently demonstrated when they plucked Harry Hughes out of also-ran obscurity in 1978 and put him in the governor's office.

More recently, 45,879 Maryland Democrats -- nearly one in 10 of those who voted -- pulled the "uncommitteed" lever in the May 13 primary.

Anderson's half-hour address to the lunchtime crowd here seemed designed to appeal to this independent-mindedness. He drew loud applause when he said he was challenging not the two-party system but "the nominating process that could serve up two candidates so unacceptable to millions and millions of American people."

Anderson also drew laughs and cheers when he said that, although presidential press secretary Jody Powell had declared campaign "fantasyland," Democratic National Committee officials were setting aside $225,000 for the legal fight to keep him off the ballot in many states.

"That's a pretty expensive fantasy isn't it?" he asked. Anderson abandoned his quest for the Republican nomination and declared as an independent on April 2.

Anderson's remarks had two themes, the need for diversity in the democratic political process and what he called the failures of Carter's leadership and his energy, economic and foreign policies. Anderson had little to say about Republican candidate Ronald Reagan.

Citing the latest federal statistics showing unemployment up to 7.8 percent, Anderson scoffed at the president's assertion that 'We're turning the corner.' He said that Carter "sounds just like Herbert Hoover --prosperity is just around the corner."

While Anderson's Maryland coordinator, Bert Booth -- a feisty state delegate from Baltimore County -- was making rose-tinged predictions for Anderson and saying he could carry the state in November, political observers in Virginia and the District were much more pessimistic about his chances there.

In sum, they said that although Anderson's politics defy easy labeling, he is probably seen as too liberal to win much support in Virginia and too conservative to pull in many votes in the District.

"Virginia is the most conservative state in the union," said Bill King, an aide to the state's Republican Sen. John Warner. "I don't see John Anderson doing well in Virginia.

"What John is standing for in the present election is almost anathema to the political philosophy of the large majority of Virginia voters," he said.

In the District, aides to Mayor Marion Barry -- who supports President Carter -- said Anderson's voting record, which has led to lukewarm approval ratings by such groups as the liberal Americans for Democratic Action, would do little to win him support in this largely Democratic, largely black city.