1213-D
The General Radio 1213-D Unit Time/Frequency Calibrator was introduced in Catalog Q (1961) and remained available through Catalog R (1963).
The Type 1213-D is a two-part device. The first part produces four calibration signals rich in harmonics. The signals are generated by a 5 MHz crystal oscillator and is doubled to 10 MHz, followed by three stages of dividers to produce one of four marker outputs. The selected output is fed to a harmonic generator and made available at the front panel when the 1213-D is in the "Timing Markers" function.
The second part of the 1213-D is a built in mixer-amplifier. When switched to the "Audio Beat Signal" function, the panel jack becomes an input. Mixed with the internal selected marker signal, the input signal creates a beat note at the audio binding posts. Using this output to observe a zero beat with headphones, or by observing Lissajous figures on an oscilloscope, the input signal can be calibrated.
As a unit oscillator, the 1213-D requires an external power supply, the type 1203-B is recommended.
Specifications
- Frequencies: 10 MHz, 1 MHz, 100 kHz, 10 kHz
- Frequency Adjustment: ±5 ppm
- Amplitude: 5 Vp-p @ 10 MHz; 30 Vp-p at lower output frequencies from pulse amplifier
- RF Harmonics: Usable to 1000 MHz from 10 MHz output, to 500 MHz from 1 MHz output, to 100 Mc from 100 kHz output, and to 10 Mc from 10 kHz output
