downloadFile():Observable<Pcm[]> {
let headers: HttpHeaders = new HttpHeaders()
.set('SENSOR_ID', 'asusD6')
.set('startDate', '20190513140000')
.set('endDate', '20190513140011')
.set('debugLevel', '1')
.set('Cycle', '10')
.set('Multipart', '1')
.set('Audio', '1')
.set('Accept', 'application/json')
.set('Content-Type', 'application/json');
return this.http.get<Pcm[]>(this.ROOT_URL + '/pcm_json',{headers,responseType:'json'})
}
a