IPC 6 English version H03L !A-H03L 7/26

H03L-H03L00726

SECTION H– ELECTRICITY

H 03

BASIC ELECTRONIC CIRCUITRY

H 03 L

AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (of dynamo-electric generators H 02 P) [3]

Notes

(1)

This subclass covers:

–

automatic control circuits for generators of electronic oscillations or pulses; [3]

–

starting, synchronisation, or stabilisation circuits for generators where the type of generator is irrelevant or unspecified. [3]

(2)

This subclass does not cover stabilisation or starting circuits specially adapted to only one specific type of generator, which are covered by subclasses H 03 B, H 03 K. [3]

(3)

In this subclass, the following expression is used with the meaning indicated:

–

"automatic control" covers only closed loop systems. [3]

Stabilisation of generator output against variations of physical values, e.g. power supply (automatic control H 03 L 5/00, H 03 L 7/00) [3]

against variations of temperature only [3]

Constructional details for maintaining temperature constant [3]

Starting of generators [3]

Automatic control of voltage, current, or power [3]

of power [3]

Automatic control of frequency or phase; Synchronisation (tuning of resonant circuits in general H 03 J; synchronising in digital communication systems, see the relevant groups in class H 04) [3]

using a frequency discriminator comprising a passive frequency-determining element [3]

wherein the frequency-determining element comprises distributed inductance and capacitance [3]

using a reference signal applied to a frequency- or phase-locked loop [3]

using several loops, e.g. for redundant clock signal generation (for indirect frequency synthesis H 03 L 7/22) [5]

Details of the phase-locked loop [3]

081

provided with an additional controlled phase shifter [5]

083

the reference signal being additionally directly applied to the generator (direct frequency synchronisation without loop H 03 L 7/24) [5]

085

concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal (H 03 L 7/10 takes precedence; frequency or phase detection comparison in general H 03 D 3/00, H 03 D 13/00) [5]

087

using at least two phase detectors or a frequency and phase detector in the loop [5]

089

the phase or frequency detector generating up-down pulses (H 03 L 7/087 takes precedence) [5]

091

the phase or frequency detector using a sampling device (H 03 L 7/087 takes precedence) [5]

093

using special filtering or amplification characteristics in the loop (H 03 L 7/087 to H 03 L 7/091 take precedence) [5]

095

using a lock detector (H 03 L 7/087 takes precedence) [5]

097

using a comparator for comparing the voltages obtained from two frequency to voltage converters [5]

099

concerning mainly the controlled oscillator of the loop [5]

for assuring initial synchronisation or for broadening the capture range [3]

107

using a variable transfer function for the loop, e.g. low pass filter having a variable bandwidth [5]

113

using frequency discriminator [5]

using a scanning signal (tuning circuits with automatic scanning over a band of frequencies H 03 J 7/18) [3]

for assuring constant frequency when supply or correction voltages fail [3]

Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop [3]

using a frequency divider or counter in the loop (H 03 L 7/20, H 03 L 7/22 take precedence) [3]

181

a numerical count result being used for locking the loop, the counter counting during fixed time intervals [5]

183

a time difference being used for locking the loop, the counter counting between fixed numbers or the frequency divider dividing by a fixed number [5]

185

using a mixer in the loop (H 03 L 7/187 to H 03 L 7/195 take precedence) [5]

187

using means for coarse tuning the voltage controlled oscillator of the loop (H 03 L 7/191 to H 03 L 7/195 take precedence) [5]

189

comprising a D/A converter for generating a coarse tuning voltage [5]

191

using at least two different signals from the frequency divider or the counter for determining the time difference (H 03 L 7/193, H 03 L 7/195 take precedence) [5]

193

the frequency divider/counter comprising a commutable pre-divider, e.g. a two modulus divider (pulse counters/frequency dividers H 03 K 21/00 to H 03 K 29/00) [5]

195

in which the counter of the loop counts between two different non zero numbers, e.g. for generating an offset frequency (H 03 L 7/193 takes precedence; pulse counters for predetermined counting H 03 K 21/00 to H 03 K 29/00) [5]

197

a time difference being used for locking the loop, the counter counting between numbers which are variable in time or the frequency divider dividing by a factor variable in time, e.g. for obtaining fractional frequency division [5]

199

with reset of the frequency divider or the counter, e.g. for assuring initial synchronisation [5]

using a harmonic phase-locked loop, i.e. a loop which can be locked to one of a number of harmonically related frequencies applied to it (H 03 L 7/22 takes precedence) [3]

using more than one loop [3]

with pulse counters or frequency dividers [5]

using a reference signal directly applied to the generator [3]

using energy levels of molecules, atoms, or subatomic particles as a frequency reference [3]