Radio receivers
AssigneeU.S. Philips Corporation
InventorsKnud Holtvoeth, Andreas Wichern, Wilfried Knop
Life of this patent
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Abstract
A receiver has a crystal oscillator (10) whose frequency can be adjusted in response to temperature compensation (TC) and automatic frequency control (afc) signals. The TC and afc signals are summed and applied to an op-amp (70) having a fixed gain functioning as a current to voltage converter. An output of the op-amp (70) is applied to the crystal oscillator (10). If the receiver is switched--on and--off in accordance with say a time division protocol, the output of the op-amp (70) is applied by way of a switch (72) to a storage circuit (30,C) which when the switch is open applies a bias voltage on the crystal oscillator (10) to maintain its output frequency.
Claims14
A receiver including a temperature controlled crystal oscillator having an input for an analog voltage tuning signal, first means for generating an analog temperature compensating control signal, second means for producing an analog automatic frequency control signal, means for continuously summing the analog temperature compensating and automatic frequency control signals and producing an analog sum signal, and current to voltage conversion means having an input for the analog sum signal and an output coupled to said input of the oscillator.
An integrated receiver comprising a frequency down conversion stage having a first input for a received signal, a second input for a local oscillator signal supplied by a temperature controlled crystal oscillator and an output for a down-converted signal, first means for generating an analog temperature compensating control signal, second means for producing an analog automatic frequency control signal, means for continuously summing the analog temperature compensating and automatic frequency control signals and producing an analog sum signal, and current to voltage conversion means having an input for the analog sum signal and an output coupled to an input of the oscillator for an analog tuning signal.
Dependencies are inferred from the claim text.