Abstract:
The AM receiver comprises an input stage(11, 12) for receiving the compatible stereo signal of (I+L+R)cos(Wct+0) and translating the signal to an intermediate frequency signal. A detector(16) is coupled to the input stage for providing the output signal which is proportional to the (L-R)cos. A corrector circuit(17, 22, 23, 25) which is coupled to the detector(16) provides a correctional signal for use in restoring exact sum and difference signals.
Abstract:
A color television recording system is shown wherein trains of pulses are produced by a CRT sweeping recorded color information on a film. Each train of pulses is preceded by several pulses representative of a low frequency of the system and several pulses representative of a high frequency of the system. The two groups of pulses are separated and detected to provide DC signals which are compared to produce a difference signal. The difference signal is utilized to peak an amplifier in the recording system so that the frequency response of the system is at a predetermined ratio for the high and low frequencies.
Abstract:
Demodulation of standard FM multiplex stereophonic signals is accomplished without using a 38kHz frequency doubler operating in response to the 19kHz pilot tone signal. The first stage of demodulation is accomplished in a first gated symmetrical time gate which is supplied with the composite input signals and is switched in synchronism with the 19kHz pilot signal. The two outputs of this time gate then constitute inputs to second and third time gates which are synchronously switched by a 19kHz signal at quadrature with the signal switching the first time gate. By combining appropriate outputs of the second and third time gates, the demodulated left and right audio information is obtained.
Abstract:
A color television receiver uses an integrated circuit to provide the subcarrier reference signals and ACC control voltage for the receiver. The circuit includes a first differential amplifier, unbalanced at the burst signal frequency, operated as the color reference oscillator to provide first and second differently phased output signals which are applied to a pair of differential steering gates. A phase-shift hue control of the color reference signal is obtained by adding selected outputs of the pair of differential steering gates. In addition, a differential amplifier is operated as a diodeless detector for deriving an ACC voltage from the oscillator output when burst signals are applied to the input of the oscillator.
Abstract:
A color television receiver uses an integrated circuit to provide the subcarrier reference signals and ACC control voltage for the receiver. The circuit includes a first differential amplifier, unbalanced at the burst signal frequency, operated as the color reference oscillator to provide first and second differently phased output signals which are applied to a pair of differential steering gates. A phase-shift hue control of the color reference signal is obtained by adding selected outputs of the pair of differential steering gates. In addition, a differential amplifier is operated as a diodeless detector for deriving an ACC voltage from the oscillator output when burst signals are applied to the input of the oscillator.
Abstract:
A stereo-effect enhancement system for increasing the apparent spatial separation in a multi-channel audio system includes variable gain amplifiers and comparator circuits which compare the amplitudes of the audio input signals and adjust the gain of the variable gain amplifiers in accordance with the ratio of the amplitudes of the audio input signals. Spatially expanded two channel stereo, pseudo three channel stereo, pseudo four channel stereo or automatic stereo balance control may be achieved by variously combining the audio signals from the enhancement system with the unmodified audio input signals.
Abstract:
There is disclosed an audio amplifying output circuit for a receiver which includes biasing means for operating the output transistor to a minimum operating current level. The circuit is DC coupled to the preceeding stage as for example, the IF detector stage, so as to receive the DC component of the detected carrier signal. The DC component of the detected carrier signal is applied directly to the base of the transistor to increase its collector current in accordance with the amplitude of the driving signal thereby preventing transistor cut-off when signals of higher levels are received thereby.
Abstract:
Transistorized differential circuits include a biasing system that substantially reduces the need for resistors in the base circuits of the transistors being biased. An inductor coupled between the base of one of the transistors and a power supply forward biases the base-emitter junction of the transistor, and the other base is coupled to the same point of the power supply to bias the transistor so that the voltages at the bases of the transistors are substantially equal to each other, and are at substantially the voltage of the power supply to which the inductor is connected. This technique is applicable to balanced or unbalanced differential transistor circuits, and may be employed in amplifiers, mixers, limiters, multipliers and oscillators and in other small signal applications.