Abstract: A switchable low pass filter includes a first switch connected to a first resistive element, a second switch connected to a second resistive element, and a capacitive element connected to the first and second resistive elements. The switchable low pass filter also includes a controller connected to the first switch and the second switch, the controller operative to open and close at least one of the first switch and the second switch. A method for producing a pulse density modulated signal whose pulse timing is jittered includes the following steps; adding a substantially random number and a multi-bit number to a value stored in a flip flop, thereby producing a sum; if the sum is less than an upper limit, storing the sum in the flip flop, thereby replacing the value; if the sum is not less than the upper limit, producing a pulse, subtracting the upper limit from the sum, thereby producing a result, and storing the result in a flip flop; and repeating the steps.