<PAGE>   1





                         DISCOVER CARD TRUST 1993 B              Exhibit 99 (A)

                     Credit Card Pass-Through Certificates


                          Distribution and Performance
                         Annual Aggregate Report - 1997


        Under the Pooling and Servicing Agreement dated as of February 1, 1993
(the "Agreement") by and among Greenwood Trust Company (the "Servicer"),
Discover Receivables Financing Group, Inc. and Wilmington Trust Company, as
Trustee, the Servicer is required to prepare certain information each month
regarding current distributions to Investor Certificateholders and the
performance of the Trust during the previous month.  For purposes of filing
Form 10-K, certain information is required to be prepared with respect to the
Distribution Dates occurring during the calendar year 1997.  The information
which is required to be prepared with respect to such Distribution Dates
related to the year mentioned above is set forth below.  Certain of the
information is presented on the basis of an original principal amount of $1,000
per Investor Certificate.  Certain other information is presented based upon
the aggregate amounts for the Trust as a whole.

A. Information Regarding the Aggregate Distributions for 1997

   1. Class A Certificates
      (a) The aggregate amount of the distribution to Class
          A Certificateholders on the related Distribution
          Dates.                                                $15,525,000.00

      (b) The amount of the distribution set forth in
          paragraph (a) above in respect of interest.           $15,525,000.00

      (c) The amount of the distribution set forth in
          paragraph (a) above in respect of principal.                   $0.00

      (d) The amount of the distribution set forth in
          paragraph (a) above, per $1,000 interest.              $67.500000000

      (e) The amount of the distribution set forth in
          paragraph (b) above, per $1,000 interest.              $67.500000000

      (f) The amount of the distribution set forth in
          Paragraph (c) above, per $1,000 interest.               $0.000000000

   2. Class B Certificates
      (a) The aggregate amount of the distribution to Class
          B Certificateholders on the related Distribution
          Dates.                                                 $1,633,000.00

      (b) The amount of the distribution set forth in
          paragraph (a) above in respect of interest.            $1,633,000.00


<PAGE>   2


      (c) The amount of the distribution set forth in
          paragraph (a) above in respect of principal.                   $0.00

      (d) The amount of the distribution set forth in
          paragraph (a) above, per $1,000 interest.              $71.000000000

      (e) The amount of the distribution set forth in
          paragraph (b) above, per $1,000 interest.              $71.000000000

      (f) The amount of the distribution set forth in
          Paragraph (c) above, per $1,000 interest.               $0.000000000

B. Information Regarding the Performance of the Trust

   1. Collections of Receivables
      (a) The aggregate amount of Finance Charge Collections
          processed during the related Due Periods.             $57,100,370.70

      (b) The aggregate amount of Principal Collections
          processed during the related Due Period.             $622,285,032.05

      (c) The aggregate amount of Finance Charge Collections
          processed during the related Due Periods which was
          allocated in respect of the Investor Certificates.    $45,545,486.45

      (d) The aggregate amount of Principal Collections
          processed during the related Due Periods which was
          allocated in respect of the Investor Certificates.   $495,958,712.70

      (e) The aggregate amount of Finance Charge Collections
          processed during the related Due Periods which was
          allocated in respect of the Class A  Certificates.    $41,405,021.55

      (f) The aggregate amount of Principal Collections
          processed during the related Due Periods which was
          allocated in respect of the  Class A Certificates.   $450,872,222.47

      (g) The aggregate amount of Finance Charge Collections
          processed during the related Due Periods which was
          allocated in  respect of the Class B Certificates.     $4,140,464.90

      (h) The aggregate amount of Principal Collections
          processed during the related Due Periods which was
          allocated in respect of the  Class B Certificates.    $45,086,490.23

      (i) The aggregate amount of Finance Charge Collections
          processed during the related Due Periods which was
          allocated  in respect of the  Seller  Certificate.    $11,554,884.25

      (j) The aggregate amount of Principal Collections
          processed during the related Due Periods which was
          allocated in respect  of the  Seller  Certificate.   $126,326,319.35


<PAGE>   3


   2. Investor Losses; Reimbursement of Charge-Offs
      (a) The aggregate amount of Class A Investor Losses,
          as defined in Section 4.04 (b) of the Agreement,
          during the related Due Periods.                                $0.00

      (b) The aggregate amount of Class B Investor Losses,
          as defined in Section 4.04 (b) of the Agreement,
          during the related Due Periods.                                $0.00

      (c) The amount of Class A Investor Losses set forth in
          paragraph (a) above, per $1,000 interest.               $0.000000000

      (d) The amount of Class B Investor Losses set forth in
          paragraph (b) above, per $1,000 interest.               $0.000000000

      (e) The total amount reimbursed to the Trust in the
          current year pursuant to Section 4.04 (c) of the
          Agreement, if any, in respect of Class A Investor
          Losses.                                                        $0.00

      (f) The total amount reimbursed to the Trust in the
          current year pursuant to Section 4.04 (c) of the
          Agreement, if any, in respect of Class B Investor
          Losses.                                                        $0.00

      (g) The amount set forth in paragraph (e) above per
          $1,000 interest.                                        $0.000000000

      (h) The amount set forth in paragraph (f) above, per
          $1,000 interest.                                        $0.000000000

      (i) The aggregate amount of unreimbursed Class A
          Investor Losses in the Trust as of the end of the
          calendar year 1997.                                            $0.00

      (j) The aggregate amount of unreimbursed Class B
          Investor Losses in the Trust as of the end of the
          calendar year 1997.                                            $0.00

      (k) The amount set forth in paragraph (i) above, per
          $1,000 interest.                                        $0.000000000

      (l) The amount set forth in paragraph (j) above, per
          $1,000 interest.                                        $0.000000000

   3. Investor Servicing Fee
      (a) The amount of the Class A Monthly Servicing Fee
          payable by the Trust to the Servicer for the year
          ended December 31, 1997.                               $4,600,033.00

      (b) The amount of the Class B Monthly Servicing  Fee
          payable by the Trust to the Servicer for the year
          ended December 31, 1997.                                 $459,997.71


<PAGE>   4

   4. Available Class B Credit Enhancement Amount
      (a) The amount available to be drawn under the Class B
          Credit Enhancement pursuant to Section 4.03 (c)
          (i), (G) and (H) of the Agreement as of the end of
          the day on December 31, 1997.                         $12,650,000.00

      (b) The amount set forth in paragraph (a) above as a
          percentage of the Class B Interest.                            55.00%

   5. The Pool Factor

          The Pool Factor represents the  ratio of the amount
          of the Investor Interest as of the end of the day on
          December 31, 1997 to the amount of the Investor
          Interest as of the Closing Date. The amount of a
          Certificateholder's pro-rata share of the Investor
          Interest can be determined by multiplying the original
          denomination of the Certificate- holder's Certificate
          by the Pool Factor.

          (a) Class A Certificates.                                1.000000000

          (b) Class B Certificates.                                1.000000000