It took only one day for the Federal Open Market Committee to make known its desire to tighten credit another notch.On Wednesday, the Fed allowed federal funds to trade upwards to their new level of 7 3/4. This move, although anticipated, still caused a short-term rates to rise and nudged the longer-term rates up a bit as well.

Money market participants feel the federal fund rates will be at 8 percent by the end of June, which will cause rates to rise again. These rising rates indicate the Fed's concern with the excessive growth of the money supply that could fuel a strong inflationary trend to the economy.

It would seem that the key to the future course of interest rates will be determined by the strength of the economy in the third quarter of this year. If the economy is strong, the demand for credit will be strong and will push rates high.

If the economy weakens noticeably, so will the demand for credit, which will reduce the upwards pressure of interest rates.

The new 6-month savings certificates that are being issued at one-quarter percentage point above the average return on the weekly 6-month Treasury bill auction merit a couple of comments when compared to the 6-month bill itself. First, on a net true yield basis (the actual return based on the number of dollars invested), the return on the bill (which is purchased on a discount basis) is higher thatn the yield received on the 6-month savings certificate which is purchased at a face amount of $10,000. Second, the income on the certificates is subject to federal, state and local taxes, while the T-bill is subject only to federal taxes. Third, the T-bill may be sold at any time; it is very liquid. The certificate may be redeemed but it is subject to a "substantial" penalty on the interest received for a redemption prior to maturity. One disadvantage of the T-bill, of course, is that you have to make the trip to the Treasury to enter your subscription to avoid paying a fee.

The markets were nervous all week and eventually lost ground due to the Fed's nudging action and to the money figures which in effect showed another uptick.

In the corporate area, the triple-A New York Telephone issue was offered to return 8.94 percent. The issue did not sell out and eventually broke to the 9 percent level. A single-A utility sold well with a 9.60 percent return to the investor.

The triple-A, tax-exempt State of Maryland issue was 65 percent sold in a tough market environment. Prices had to be lowered to facilitate sales. The Bond Buyer Index jumped 10/100 to 6.26 percent to show how tough the market was.

Of particular interest this week is the $1.75 billion Treasury offering of a 15-year, 1-month bond. The bonds will be due 8/15/93 and will come in minimum denomination of $1,000. Tenders should be entered at the Treasury Department or the local Federal Reserve banks no later than 1:30 p.m. on Wednesday. A deposit of 5 percent of the face amount being applied for is required. Final payments wil be due July 11 if paid for in cash, on July 7 if paid for with a check drawn on a local bank, and on July 6 if paid for by a check drawn on a bank outside the local Federal Reserve district. Checks should be made payable to "Bureau of the Public Debt." A price guess would be 850-860 percent.

The municipal market will offer another high-grade name, the State of New Jersey. Also of interest is a $69 million North Carolina Hospital bond, the Duke University Hospital project. Tax-exempt yields on this issue could exceed 7 percent on the longer maturities.

The corporate area will feature a Baltimore Gas and Electric Co. issue, plus $100 million in McDonalds Corp. sinking fund notes due 6/15/88.