1141-A
The General Radio 1141-A Audio-Frequency Meter was introduced in Catalog L (1948) and remained available through Catalog M (1951). It did not appear in Catalog N (1954).
The 1141-A is an analog direct-reading frequency meter "completely covering the usual audio-frequency range and extending somewhat beyond that range in both directions"[1]. It makes use of the Wien bridge circuit, along with an external detector such as a pair of high impedance headphones, to measure the input frequency. The operator selects the frequency range and turns the frequency dial to minimize the signal at the detector. The input frequency is then read from the range selection multiplier the setting of the frequency dial.
The 1141-A may also be used as a band-elimination filter, or to measure total harmonic distortion.
Specifications
- Frequency: 20 Hz to 20 kHz in 3 decade ranges
- Accuracy: ±0.5% over the entire frequency range
- Dial: 6-inch dial with slow-motion drive through an angle of about 320°, giving a scale length of about 17 inches for each 10 to 1 frequency range. The total scale length is thus over 4 feet
- Input Impedance: 3 to 10 kΩ, the smaller value corresponding to the higher frequencies
- Input Voltage: 110 volts rms, maximum
- Output Impedance: 1 to 4 kΩ, the smaller value corresponding to the higher frequencies
- Controls: Frequency dial, range selector switch, and resistance-balance control
Links
ToDo: link to the February 1948 General Radio Experimenter
Photos
- ↑ "A Bridge-Type Audio-Frequency Meter", February 1948, General Radio Experimenter