Abstract: A clocked comparator having an input differential amplifier, a sample and hold circuit, and a load stage. The load stage including a first transistor whose channel is connected between a first terminal and a first node, a second transistor whose channel is connected between a second terminal and a second node, a third transistor whose channel is connected between the first node, a third terminal and a fourth transistor whose channel is connected between the second node and the third terminal and a switch between the first and the second terminal. The gates of the first and the fourth transistor are connected to the first terminal. The gates of the second and the third transistor are connected to the second terminal. When the switch is closed the first and the second transistor form a positive differential impedance between the first and the second terminal. When the switch is open the cross-coupled third and fourth transistors form a negative differential impedance between the first and the second terminal.

Abstract: A load stage including a first transistor whose channel is connected between a first terminal and a first node, a second transistor whose channel is connected between a second terminal and a second node, a third transistor whose channel is connected between the first node, a third terminal and a fourth transistor whose channel is connected between the second node and the third terminal and a switch between the first and the second terminal. The gates of the first and the fourth transistor are connected to the first terminal. The gates of the second and the third transistor are connected to the second terminal. The load stage also includes a switch connected between the first node and the second node. When the switch is closed the first and the second transistor form a positive differential impedance between the first and the second terminal. When the switch is open the cross-coupled third and fourth transistors form a negative differential impedance between the first and the second terminal.

Abstract: A clocked comparator circuit comprises an input stage and a sample-and-hold circuit and an amplifier-latch circuit coupled to the output of the input stage. The sample-and-hold circuit provides an accurate offset-voltage compensation and the amplifier-latch circuit provides a high operating speed by means of a switchable current source (S6, T11). Switches are provided so that the amplifier-latch circuit constitutes a differential load having a high positive impedance during a first state of a clock signal, a low positive impedance during a next state of the clock signal, and a negative impedance during a following state of the clock signal.

Abstract: A digital phase-locked-loop circuit is provided for deriving from a sequence of samples (J.sub.1, . . . J.sub.20) of a band-limited data signal (Vt), the phase of the data signal at the sampling instants. The circuit includes a discrete-time oscillator 10 for generating a sequence of phase values (F.sub.1, . . . F.sub.20) which characterize a periodic signal (Vk1) having an amplitude which varies as a linear function of time between two constant limit values (E.sub.1, -E). The frequency of the periodic signal (Vk1) characterized by the phase values is proportional to a control value (I). An interpolation circuit (2) derives from the samples (J.sub.1, . . . J.sub.20) the relative positions (tf/T) occupied by the detection-level crossings of the data signal (Vt) relative to the sampling instants. A phase detector (3) derives the difference (.DELTA.F) between the actual phase of the data signal (Vt) and the phase as indicated by the phase values (F) from the relative positions (tf/T) and the phase values (F).

Abstract: A digital phase-locked-loop circuit is provided for deriving from a sequence of samples (J.sub.1, . . . J.sub.20) of a band-limited data signal (Vt), the phase of the data signal at the sampling instants. The circuit includes a discrete-time oscillator 10 for generating a sequence of phase values (F.sub.2, . . . F.sub.20) which characterize a periodic signal (Vk1) having an amplitude which varies as a linear function of time between two constant limit values (E, -E). The frequency of the periodic signal (Vk1) characterized by the phase values is proportional to a control value (I). An interpolation circuit (2) derives from the samples (J.sub.1, . . . J.sub.20) the relative positions (tf/T) occupied by the detection-level crossings of the data signal (Vt) relative to the sampling instants. A phase detector (3) derives the difference (.DELTA.F) between the actual phase of the data signal (Vt) and the phase as indicated by the phase values (F) from said relative positions (tf/T) and the phase values (F).