This paper presents a method of calculation for the frequency transformation of a low-pass filter into a band-pass filter with a minimum number of inductances. When the chain matrix of a low-pass filter with the order

is factorized into the product of

partial matrices, the circuit elements of the required band-pass filter can be found one by one from these partial matrices by means of

recurrence equations. The computation formulas and rules, which are described in detail in this paper, are extremely suitable for the use of an automatic digital computer. The flow charts of the programing for these calculation procedures are also illustrated in some detail with a numerical example, which is carried out by the transistorized digital computer Type NEAC-2203.