NL97484C - Frequency detector for determining the characteristic frequency of a vibration occurring within a certain conversation band - Google Patents
Frequency detector for determining the characteristic frequency of a vibration occurring within a certain conversation bandInfo
- Publication number
- NL97484C NL97484C NL221597A NL221597A NL97484C NL 97484 C NL97484 C NL 97484C NL 221597 A NL221597 A NL 221597A NL 221597 A NL221597 A NL 221597A NL 97484 C NL97484 C NL 97484C
- Authority
- NL
- Netherlands
- Prior art keywords
- frequency
- amplitude
- output
- voltage
- ratio
- Prior art date
Links
- 230000010355 oscillation Effects 0.000 abstract 2
- 238000001514 detection method Methods 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
- G01R27/10—Measuring resistance by measuring both voltage and current using two-coil or crossed-coil instruments forming quotient
- G01R27/12—Measuring resistance by measuring both voltage and current using two-coil or crossed-coil instruments forming quotient using hand generators, e.g. meggers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G10L25/00—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Audiology, Speech & Language Pathology (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- Computational Linguistics (AREA)
- Human Computer Interaction (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Measurement Of Current Or Voltage (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Measuring Frequencies, Analyzing Spectra (AREA)
Abstract
844,561. Frequency discriminators. PHILIPS ELECTRICAL INDUSTRIES Ltd. Oct. 10, 1958 [Oct. 14, 1957], No. 32423/58. Class 40(5). [Also in Group XXXVI] In a frequency detector for the detection of the variation of a characteristic speech frequency situated within a speech sub-band, the speech sub-band, which is selected by means of a filter 4, is supplied to two channels 6, 7 connected in parallel, the channel 6 comprising a differentiating network 8 and a rectifier 9 and the second a rectifier 11, the output voltages from the channel being fed to a ratio meter 13 the output voltage of which is the ratio of the amplitudes of the channel output voltages and a measure of the frequency. Low-pass filters 10 and 12 are included in branches 6, 7 respectively, and, if the input voltage of rectifier 11 is a (t) at a certain instant that to rectifier 9 is #a(t), so that the ratio of the output voltages of filters 10 and 12 is proportional to awdt/adt and therefore to the frequency. In the embodiment shown, the output direct voltages of filters 10, 12 are converted into alternating voltages of frequencies fi f 2 , corresponding in amplitude to the direct voltages, by means of amplitude modulators 15, 16, carrier wave oscillators 17, 18 of frequencies f 1 f 2 and output filters 19, 20, the outputs of the oscillators and filters being connected through attenuators 21, 22 to adjust the strength ratio of the carrierwave oscillations. A ratio meter for use in the detector is shown in Fig. 4. The alternating voltage derived from channel 6 of frequency f 1 and amplitude-modulated by the rectified differentiated input signal is applied to the grid of a pentode 25 through a resistor 23, the alternating voltage derived from channel 7 of frequency f 2 and amplitude modulated by the rectified input signal being applied to the grid through a resistor 26. Slope control is provided for the pentode 25 and the amplitude of oscillations at frequency f 2 at the output of pentode 25 is therefore kept constant, so that the slope of the pentode 25 varies inversely as the amplitude of the input voltage at frequency f 2 . The voltage at frequency fi is selected by a filter 30 and rectified, the output at 38, 39 being a direct voltage proportional to the amplitude ratio between the output voltages of channels 6 and 7. In the embodiment of Fig. 5, the ratio is determined by amplitude limitation instead of slope control. An amplitude limiter comprising rectifiers 45, 46 has an output consisting of a voltage of frequency f 2 modulated by the voltage of frequency f 1 the frequency deviation of said f.m. voltage being proportional to f 1 : f 2 , the amplitude of f 1 < amplitude of f 2 . The limiter output is fed to an amplifier 51 and a filter 52 tuned to fi, the voltage from this filter being then rectified and giving a direct voltage output which varies as the amplitude ratio of the input voltages of frequencies fi and f 2 . Alternatively the ratio meters may be replaced by one in which the output voltages of channels 6, 7 may be converted into voltages of equal frequencies, the output alternating voltage of channel 6 being subsequently shifted 90 degrees in phase and added to the alternating voltage of channel 7 so that the phase of the sum voltage obtained varies in accordance with the desired amplitude ratio.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL221597A NL97484C (en) | 1957-10-14 | 1957-10-14 | Frequency detector for determining the characteristic frequency of a vibration occurring within a certain conversation band |
US764073A US2995707A (en) | 1957-10-14 | 1958-09-29 | Frequency detector |
DEN15693A DE1151284B (en) | 1957-10-14 | 1958-10-10 | Frequency analyzer for determining the course of a characteristic speech frequency lying in a speech frequency subband |
GB32423/58A GB844561A (en) | 1957-10-14 | 1958-10-10 | Improvements in or relating to frequency detectors |
JP2906258A JPS368093B1 (en) | 1957-10-14 | 1958-10-11 | |
FR1212914D FR1212914A (en) | 1957-10-14 | 1958-10-13 | Frequency detector |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL221597A NL97484C (en) | 1957-10-14 | 1957-10-14 | Frequency detector for determining the characteristic frequency of a vibration occurring within a certain conversation band |
Publications (1)
Publication Number | Publication Date |
---|---|
NL97484C true NL97484C (en) | 1961-03-15 |
Family
ID=1838804
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
NL221597A NL97484C (en) | 1957-10-14 | 1957-10-14 | Frequency detector for determining the characteristic frequency of a vibration occurring within a certain conversation band |
Country Status (6)
Country | Link |
---|---|
US (1) | US2995707A (en) |
JP (1) | JPS368093B1 (en) |
DE (1) | DE1151284B (en) |
FR (1) | FR1212914A (en) |
GB (1) | GB844561A (en) |
NL (1) | NL97484C (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5129860A (en) * | 1974-09-06 | 1976-03-13 | Matsushita Electric Ind Co Ltd | Fmmam henkanki |
WO1986006189A1 (en) * | 1985-04-10 | 1986-10-23 | Matsushita Electric Industrial Co., Ltd. | Control circuit |
TWI672004B (en) * | 2018-12-11 | 2019-09-11 | 矽統科技股份有限公司 | Frequency detector |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2896161A (en) * | 1942-06-30 | 1959-07-21 | Bessie E Fox | Measuring system |
US2418284A (en) * | 1943-04-24 | 1947-04-01 | Bendix Aviat Corp | Differential voltage measuring circuit |
US2541067A (en) * | 1944-11-30 | 1951-02-13 | Sperry Corp | Frequency responsive device |
US2576249A (en) * | 1947-08-28 | 1951-11-27 | Bell Telephone Labor Inc | Level ratio measuring system |
US2711516A (en) * | 1949-10-29 | 1955-06-21 | Rca Corp | Frequency discriminatory systems |
GB788565A (en) * | 1954-08-11 | 1958-01-02 | Gen Electric | Improvements in and relating to frequency response determining apparatus |
US2857465A (en) * | 1955-11-21 | 1958-10-21 | Bell Telephone Labor Inc | Vocoder transmission system |
-
1957
- 1957-10-14 NL NL221597A patent/NL97484C/en active
-
1958
- 1958-09-29 US US764073A patent/US2995707A/en not_active Expired - Lifetime
- 1958-10-10 DE DEN15693A patent/DE1151284B/en active Pending
- 1958-10-10 GB GB32423/58A patent/GB844561A/en not_active Expired
- 1958-10-11 JP JP2906258A patent/JPS368093B1/ja active Pending
- 1958-10-13 FR FR1212914D patent/FR1212914A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
GB844561A (en) | 1960-08-17 |
US2995707A (en) | 1961-08-08 |
JPS368093B1 (en) | 1961-06-20 |
DE1151284B (en) | 1963-07-11 |
FR1212914A (en) | 1960-03-28 |
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