Patent ID: 6215369
Filing Date: 2001-04-10
Classification: H03B

Abstract:
A controllable oscillator, comprising a first (R.sub.c,M.sub.s1,M.sub.s2,R'.sub.c') and a second (R.sub.1,M.sub.i1,M.sub.i2,R.sub.2) amplifier which are provided with inputs (V.sub.cc,V.sub.ee) for supply voltage and at least one controllable current source (I.sub.1,I.sub.2) for controlling the output frequency of the oscillator, which amplifiers both comprise a first (R.sub.c,M.sub.s1 ;R.sub.1,M.sub.i1) and a second (R'.sub.c',M.sub.s2 ;R.sub.2,M.sub.i2) branch, where both the first and the second branch have an input (M.sub.s1,M.sub.s2 ;M.sub.i1,M.sub.i2) and an output (V.sub.out,NV.sub.out ;V'.sub.out,NV'.sub.out) for electrical signals, characterized in thatthe output (V.sub.out) of the first branch of the first amplifier is connected to the input (M.sub.i2) of the second branch of the second amplifier,the output (NV.sub.out) of the second branch of the first amplifier is connected to the input (M.sub.i1) of the first branch of the second amplifier,the output (V'.sub.out) of the first branch of the second amplifier is connected to the input (M.sub.s1) of the first branch of the first amplifier,the output (NV'.sub.out) of the second branch of the second amplifier is connected to the input (M.sub.s2) of the second branch of the first amplifier,the output (V.sub.out) of the first branch of the first amplifier is fed back to the input (M.sub.s1) of the first branch of the first amplifier, and the output (NV.sub.out) of the second branch of the first amplifier is fed back to the input (M.sub.s2) of the second branch of the first amplifier, both of which feedbacks are done via means (M.sub.r1,M.sub.r2) for reducing the DC level of the signals from the outputs and for matching the impedances between the first and the second amplifier.