Sampling phase detector

• US 5,900,747 A
• Filed: 02/02/1998
• Issued: 05/04/1999
• Est. Priority Date: 02/03/1997
• Status: Expired due to Term

• Current Assignee: Ericsson AB (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Robert Bosch GmbH
• Inventors: Brauns, Herbert
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): ZWEIZIG, JEFFERY SHAWN
• Application Number:
  US09/017,427
• Time in Patent Office: 456 Days
• Field of Search: 327/2, 327/3, 327/7, 327/9, 327/493, 327/498, 327/583, 327/585, 327/586
• US Class Current: 327/9
• CPC Class Codes: G01R 25/005 Circuits for comparing several input signals and for indicating the result of this comparison, e.g. equal, different, greater, smaller, or for passing one of the input signals as output signal
• CPC Class Codes: H03D 13/006 and by sampling this signal by narrow pulses obtained from the second oscillation

Abstract

The sampling phase detector whose output signal (fd) has a very broad-band and a very even frequency response characteristic includes a step-recovery-diode (SRD) to which a series circuit including at least two diodes (D1,D2) is connected in parallel by means of coupling capacitors (Ck1,Ck2). An input signal is fed to the diodes (D1,D2) by means of an R/C-network (R1,R2,C3,C4) and an output signal (fd) is taken off, which corresponds to the phase shift between an input signal (fo) and a reference signal (fr). The reference signal (fr) is fed to the step-recovery-diode (SRD) via a balancing transformer (Tr). Decoupling resistors (Rs1,Rs2) are included in the connecting lines from the balancing transformer (Tr) to the step-recovery-diode (SRD), which damp interfering resonances or reflections of the balancing transformer.

Claims

1. A sampling phase detector comprising

a step-recovery-diode (SRD),

a series circuit connected in parallel to said step-recovery-diode (SRD) by means of coupling capacitors (Ck1,Ck2), said series circuit including at least two diodes (D1,D2) electrically connected in series with each other;

a balancing transformer for supplying a reference signal (fr) to said step-recovery-diode (SRD), said balancing transformer (Tr) being connected electrically to said step-recovery-diode (SRD) via respective connecting lines;

a decoupling network for supplying an input signal to said at least two diodes (D1,D2) so that an output signal characteristic of a phase shift between the input signal and the reference signal is read from the at least two diodes; and

decoupling resistors (Rs1,Rs2) connected in said connecting lines between the step-recovery-diode (SRD) and the balancing transformer;

wherein resistances of the decoupling resistors (Rs1,Rs2) are selected so that said decoupling resistors (Rs1,Rs2) damp interfering resonances or reflections between the balancing transformer (Tr) and the step-recovery-diode (SRD).

2. The sampling phase detector as defined in claim 1, further comprising an L/C network (L1,C1;

L2,C2) connected electrically with the step-recovery-diode (SRD) and wherein said L/C network includes a load resistor (Rp).

3. The sampling phase detector as defined in claim 2, further comprising respective coupling capacitors (Ck1,Ck2) connected in series with said at least two diodes (D1,D2) on respective opposite ends of said series circuit including said at least two diodes and additional resistors (Rk1,Rk2) each connected to a connection point between a respective one of the coupling capacitors (Ck1,Ck2) and the series circuit including the at least two diodes (D1,D2).

4. The sampling phase detector as defined in claim 3, further comprising a common substrate (SM) on which the coupling capacitors (Ck1,Ck2), the at least two diodes (D1,D2), the decoupling resistors (Rs1,Rs2), the L/C network (L1,C1;

L2,C2) including the load resistor (Rp) and the step-recovery-diode (SRD) are mounted using film circuit technology.

5. The sampling phase detector as defined in claim 4, wherein said additional resistors (Rk1,Rk2) which are connected to said connection points are mounted on said substrate (SM).