Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
98 words
In a video record/reproduce system using high frequency signals in the form of an amplitude modulated RF envelope of frequency modulated carrier, an automatically calibrated envelope detector circuit comprising: envelope detector means for generating an output proportional to the peaks of the amplitude modulated RF envelope; and feedback loop means responsive to selected envelope recurrent periods of known amplitude level for automatically establishing a selected reference level during the recurrent periods to continuously servo the gain of the envelope detector circuit to maintain a constant voltage change between said reference level and an RF envelope without amplitude modulation.
Claim 2
Dependent Claim
98 words
In a video record/reproduce system using high frequency signals in the form of an amplitude modulated RF envelope of frequency modulated carrier, an automatically calibrated envelope detector circuit comprising: envelope detector means for generating an output proportional to the peaks of the amplitude modulated RF envelope; and feedback loop means responsive to selected envelope recurrent periods of known amplitude level for automatically establishing a selected reference level during the recurrent periods to continuously servo the gain of the envelope detector circuit to maintain a constant voltage change between said reference level and an RF envelope without amplitude modulation.
Claim 3
Dependent Claim
34 words
The circuit of claim 1 wherein the feedback loop means is referenced to a selected voltage level during the RF envelope without amplitude modulation, to servo the gain and define the constant voltage change.
Claim 4
Dependent Claim
30 words
The circuit of claim 2 further including variable gain amplifier means coupled to the envelope detector means and responsive to the feedback loop means to correspondingly vary the gain thereof.
Claim 5
Dependent Claim
23 words
The circuit of claim 3 wherein the feedback loop means includes a capacitor selectively chargeable to said reference level during the recurrent periods.
Claim 6
Dependent Claim
37 words
The circuit of claim 4 further including circuit means coupled between said capacitor and the variable gain amplifier means during the RF envelope without amplitude modulation, for establishing the associated selected voltage level to servo the gain.
Claim 7
Dependent Claim
39 words
The circuit of claim 5 further including timing means for directing the charging of the capacitor to the reference level during the recurrent periods, and the establishing of the selected voltage level during the RF envelope without amplitude modulation.
Claim 8
Dependent Claim
101 words
The circuit of claim 6 wherein; the feedback loop means is coupled from the envelope detector means output to the input of the variable gain amplifier, the loop means including; said capacitor coupled to the envelope detector means output; said circuit means including, a differential amplifier for establishing the selected voltage level, and an RC network coupled from the differential amplifier to control the variable gain amplifier means; and switch means disposed to couple the capacitor to define the reference level during the recurrent periods, and alternately couple the capacitor to the differential amplifier during the RF envelope without amplitude modulation.
Claim 9
Dependent Claim
207 words
The circuit of claim 4 wherein the video record/reproduce system employs a transducing head for scanning along a plurality of adjacent tracks, and includes head supporting movable means for effecting lateral displacement of the transducing head with respect to the direction of the tracks in response to an oscillatory dither signal applied thereto, wherein said RF envelope is amplitude modulated by said dither signal and defines recurrent drop out intervals of zero amplitude at 100% modulation and alternate envelope periods amplitude modulated about a nominal envelope amplitude, said lateral displacement of the transducing head being detected to define a head tracking error signal indicative of the amount and direction of the head displacement from its optimum position, wherein; said envelope detector means detects the amplitude of the RF envelope as modulated by the dither signal in response to the head displacement; said feedback loop means automatically establishes said selected reference signal during the zero amplitude drop out interval, and the selected voltage level during the alternate envelope periods, to continuously servo the gain of the envelope detector circuit to maintain said content voltage change; whereby variations therefrom in the output of the envelope detector circuit represent the lateral displacement of the transducing head from its optimum position.
Claim 10
Dependent Claim
29 words
The circuit of claim 1 further including; means disposed prior to said envelope detector means for generating a known amplitude level of RF envelope during the recurrent periods thereof.
Claim 11
Dependent Claim
29 words
The circuit of claim 9 wherein the means for generating the known amplitude level of RF envelope includes diode modulator means for generating 100% modulation of the RF envelope.