An oscillator includes an input terminal, an oscillation circuit section configured to cause a resonator to resonate to output an oscillator signal, a digital input section to which a signal for controlling an oscillation frequency of the oscillation circuit section is input via the input terminal, and a first bias circuit section including a constant current source configured to supply a reference current to the digital input section.

A reference oscillator arrangement is provided for a communication apparatus capable of communicating according to a plurality of transport formats. The reference oscillator arrangement comprises a reference oscillator controller; a resonator core comprising a reference resonator and a driving circuit for the reference resonator, wherein the resonator core is arranged to provide an oscillating signal at a frequency of the reference resonator; and a reference oscillator buffer arrangement, connected to the resonator core, comprising an active circuit arranged to provide a reference oscillator output based on the oscillating signal. The reference oscillator controller is arranged to receive information about an applied transport format and control the driving circuit and/or the active circuit based on the information about the applied transport format. An oscillator arrangement, a communication device, methods therefor and a computer program are also disclosed.

A method for manufacturing oscillators of a plurality of types including a first oscillator and a second oscillator, the method includes: manufacturing the first oscillator, the manufacturing the first oscillator including a first-oscillator first step of mounting, to a first container, a first resonator element and a first circuit element configured to oscillate the first resonator element to generate a first oscillation signal, and a first-oscillator second step of mounting, to the first container, a second resonator element whose oscillation frequency is controlled based on the first oscillation signal; and manufacturing the second oscillator, the manufacturing the second oscillator including a second-oscillator first step of mounting a third resonator element and a second circuit element to a second container of the same type as the first container, the third resonator element being of the same type as the first resonator element and the second circuit element being of the same type as the first circuit element and being configured to oscillate the third resonator element to generate a second oscillation signal, and a second-oscillator second step of mounting, to the second container, a fourth resonator element whose oscillation frequency is controlled based on the second oscillation signal and whose frequency is different from the frequency of the second resonator element.